Farm system storylines: Aug./Sept. edition

Around the start of each month, MiLB.com staff breaks down the state of all 30 organizations with updates on their top prospects, Minor League affiliates and more in a feature called "Farm system storylines." This is the final entry in the series for the 2019 season.

AL East

 Baltimore Orioles
No. 4 Orioles prospectRyan Mountcastle closed out his season at Triple-A Norfolk with a nine-game hitting, going 13-for-38 (.342) with a homer and five doubles in that span. He produced a .296/.366/.546 line with six homers in 28 games after the start of August and was named International League MVP after leading the circuit in hits (162) and total bases (274). The right-handed slugger also finished with a career-best 25 homers, showing that his hit and power tools are likely Major League ready. It's the defense that has supposedly kept him from making the jump in September. A first baseman for much of the first four months, Mountcastle moved to left field primarily in August, and it looks like Baltimore wants to see more development from him on the grass before giving him a Major League look. Still, the 22-year-old did enough in 2019 to make himself part of the 2020 equation, perhaps as early as the spring. -- Sam Dykstra

 Boston Red Sox
No. 5 Red Sox prospect Tanner Houck made his Triple-A debut as a reliever on July 15 and was fairly effective in the role down the stretch, posting a 3.32 ERA with 24 strikeouts and a .191 average-against in 19 innings from Aug. 1 through the end of the season. The hope was that the 23-year-old right-hander, who relied heavily on his two-seamer and slider in college and has worked more on his four-seam and changeup in the pros, could help the Boston bullpen in September. Instead, he's headed to the Arizona Fall, where he's expected to move back to a starting role. After some struggles in his first full season in 2017, Houck is on the road to carving out a bigger role for himself in the Sox system, but it's still to be determined just which role that will be. -- SD

 New York Yankees
There wasn't a more dominant South Atlantic League pitcher down the stretch than Roansy Contreras. The No. 13 Yankees prospect was tops in the league with a 0.97 ERA, 0.54 WHIP and .122 average-against over six starts (37 innings) from the start of August onward, fanning 37 and walking only five. In the past the 19-year-old right-hander has been reliant on his plus fastball, capable of reaching 97 mph, but according to Class A Charleston coaches, the development of his curveball and changeup -- and his ability to use them in different counts -- helped him take things to a new level the past few weeks. Contreras has always been one to watch, but it'll be interesting to see whether he can carry this run of success to higher levels in 2020 and give the Yankees another promising right-hander behind Deivi Garcia. -- SD

 Tampa Bay Rays
Josh Lowe, a first-rounder in 2016 out of a Georgia high school, may have looked like he was in danger of being the forgotten Lowe brother coming into 2019, but the Rays' No. 12 prospect caught fire down the stretch, hitting .323/.388/.591 with five homers and eight stolen bases over his final 25 games with Double-A Montgomery. His 18 homers on the season were a career high by far -- beating his eight from Class A Bowling Green in 2017 -- and the same is true of his 30 stolen bases. The left-handed-hitting center fielder credited his offensive improvements with a change in approach that kept him from expanding the strike zone, and the stronger bat can be added to his plus glove, arm and speed on his scouting report. It's a lot easier to see Lowe playing alongside brother Nate sometime soon at Tropicana Field than it was a few months ago. --SD

 Toronto Blue Jays
The highlight of the month in the Jays system was likely T.J. Zeuch's nine-inning no-hitter for Triple-A Buffalo on Aug. 19, the first thrown by a Bison since Bartolo Colon on June 20, 1997. But that stellar outing was just one part of a solid string for Toronto's No. 16 prospect. Zeuch posted a 2.58 ERA over six starts after the start of August and had a 1.02 WHIP that ranked third among IL pitchers in that span. The 6-foot-7 right-hander is a bit of a throwback in that he relies heavily on getting groundball outs to be effective. To wit, he struck out only 39 over 78 innings with Buffalo over the entire season. But because of the effectiveness of his sinking fastball, Zeuch got the chance to move up to the Jays in September and made his debut Tuesday in Atlanta, giving up two earned runs in four innings. -- SD

AL Central

 Chicago White Sox
Sluggers who call Triple-A Charlotte home are always capable of putting up some crazy numbers, but even through that lens, what Zack Collins accomplished in the final weeks of the 2019 season was bonkers. Collins led all IL hitters with a .701 slugging percentage and 1.136 OPS over 26 games from Aug. 1. His 10 homers put him in a tie atop the league leaderboard with teammate and No. 5 overall prospect Luis Robert. The 24-year-old, lefty-swinging slugger was likely headed back to the South Side in September after debuting there in June, but he made that call a lot easier with his strong final push. Where he plays going forward remains a question, however. Collins featured at designated hitter in his first two games back with the White Sox, and he's played some first base in case his subpar catching skills can't keep him behind the plate. It's something worth watching in the weeks to come. -- SD

 Cleveland Indians
James Karinchak made three appearances for Triple-A Columbus in May, only to hit the injured list with a hamstring issue and not return for two months. His strikeout numbers from Aug. 1 onward, however, were nuts: 28 in 12 innings and no fewer than two in any of his 10 outings. Karinchak posted a 2.25 ERA over that span as well. Because of a high-effort delivery, walks can be a problem, and he did issue six in those dozen frames. However, he didn't walk a batter in his final five outings, fanning 14 over that run. With a plus-plus fastball and plus curve, Karinchak has the stuff to work out of the back of the bullpen; he just needs to show the control. The last few weeks have provided some hope on that front.  -- SD

 Detroit Tigers
This is a great way to make a first impression. Acquired from the Braves in a deadline deal for Shane Greene, new No. 10 Tigers prospect Joey Wentz didn't waste time showing off at Double-A Erie with a 2.10 ERA, 0.94 WHIP, 37 strikeouts and only four walks over 25 2/3 innings. That strikeout-to-walk ratio would be significant for anyone, but it's especially notable that the 21-year-old southpaw saw his free pass rate drop from 10.3 percent at Mississippi to 4.1 with Erie. Wentz has the potential to throw three above-average pitches in his fastball, curve and changeup to give him a starter's outlook, and the improvement of throwing in the zone while still getting his K's only sharpens that potential. As if the Tigers needed another dominant Double-A arm next to Casey Mize, Matt Manning, Tarik Skubal and Alex Faedo. -- SD

 Kansas City Royals
This is more like the Brady Singer that was promised. The 2018 first-rounder had a 4.17 ERA at Double-A Northwest Arkansas entering August and saw that fall to 3.47 following a strong finish with the Naturals. Singer posted a 2.45 ERA and 1.01 WHIP with 40 strikeouts and 10 walks over 36 2/3 innings in August. He tossed seven innings in three of his final four starts as well, giving up one earned run or fewer each time out. There were hopes that the Florida product could move quickly in his first full season, thanks to his plus fastball, plus slider and college pedigree, but Singer struggled in his introduction to the Texas League with a 6.28 ERA through his first six starts. His ability to make adjustments and find his Gators-level dominance again down the stretch bodes well for his development heading into 2020. -- SD

 Minnesota Twins
Top Twins pitching prospect Brusdar Graterol opened August on a rehab assignment in the Gulf Coast League. He is now in the Majors. A lot happened in between. The short version is that he returned from his shoulder injury and was placed in the bullpen at Double-A Pensacola before moving up to Triple-A Rochester on Aug. 19 in the same role. The 21-year-old right-hander is capable of touching triple digits even as a starter and has had no issue showing the plus velocity as a reliever either. That helped ease the transition as he only gave up three earned runs and struck out 11 over 10 1/3 innings in August between Double-A and Triple-A. Seeing enough from that, Twins brass brought up Graterol, who also possesses a plus slider, on the first day of September hoping he can help the big club's bullpen at a time when it's trying to hold off Cleveland in the AL Central. His first pitch in his Major League debut last Sunday: 99.6 mph. -- SD

AL West

 Houston Astros
Top prospect Kyle Tucker rebounded from a down July to post numbers more in line with his career marks. The 22-year-old produced a .293/.387/.566 slash line to go with a .942 OPS in August. Over 27 games he mashed seven homers, five doubles, drove in 21 runs and scored 22 times. He also joined an elite group on Aug. 24 when he swiped his 30th bag of the season with Round Rock and became the fifth player in the history of the PCL to join the 30 homer/30 stolen bases club. His 30 swipes paced the circuit while his 34 dingers rank fifth. The left-handed slugger joined the Astros for the first time in 2019 on Monday as part of September roster expansion and clubbed his first MLB homer Thursday night. -- Rob Terranova

 Los Angeles Angels
Jeremiah Jackson followed up his 10-homer July with a nine-dinger August. Los Angeles' No. 5 prospect posted a .338/.419/.784 slash line in August and tied the single-season Pioneer League record with 23 roundtrippers, first set in 1997 by Medicine Hat's Greg Morrison. The 2018 second-round pick from Mobile, Alabama, leads the circuit in home runs, RBIs (59) and is fourth in slugging percentage (.615). A 19-year-old shortstop, Jackson still has time to set the record with the Pioneer League season closing Saturday, but even if he doesn't, he's given Halos fans reasons for excitement. -- Shlomo Sprung

 Oakland Athletics
The weather was hot in August, and James Kaprielian matched it. The A's No. 13 prospect posted a 0.83 ERA and held hitters to a .113 average in 21 2/3 innings for Double-A Midland. Kaprielian finished 2-0 on the month in five appearances, four of which were starts, and struck out 18 while owning a 0.60 WHIP, eventually getting promoted to Triple-A Las Vegas on Aug. 31. His new teammate, Sheldon Neuse, kept swinging a big bat as the eighth-ranked Oakland prospect smashed eight homers while putting together a .295/.385/.589 slash line with 17 RBIs and 18 runs scored in August for the Aviators before pushing his way to the Bay Area this month. Alfonso Rivas, also newly promoted to the Pacific Coast League, had an excellent beginning for his new team. The A's No. 25 prospect hit .406 with a dinger, one triple, two doubles and five RBIs in eight games. -- Brian Stultz

 Seattle Mariners
It was a good month-plus for the Mariners' top three prospects. Recently promoted to Double-A Arkansas, Jarred Kelenic (No. 1) found his rhythm at the new level, hitting .253 with six homers and 17 RBIs in 21 games to close out the regular season with the Travelers. Right-hander Logan Gilbert, Seattle's No. 2 prospect, posted a 2.16 ERA in six starts, going 3-1 while fanning 39 over 33 1/3 innings for Arkansas before getting shut down in a precautionary move by general manager Jerry Dipoto. At Class A Advanced Modesto, third-ranked prospect Julio Rodriguez continued his climb, batting a blistering .468/.507/.742 with two home runs, three triples, five doubles, 17 RBIs and 12 runs scored in his 16 games for the Nuts. -- BS

 Texas Rangers
Despite missing some action, the last few weeks of the season were still a success for No. 29 Rangers prospect Eli White, who raked to a .364/.462/.545 slash line with two homers, four doubles, six RBIs and 11 runs scored for Triple-A Nashville. In six appearances (four starts) for Double-A Frisco, No. 15 prospect Tyler Phillips posted a 2.83 ERA, going 3-2 with 24 K's over 35 innings. He entered August with a 5.86 ERA in the Texas League but dropped it to 4.73 with that stretch. Fourth-ranked prospect Cole Winn put up a 2.81 ERA while holding hitters to a .198 average and fanning 25 over 25 2/3 innings for Class A Hickory. The 6-foot-2 right-hander went 2-0 in five starts with one of those wins coming Aug. 28 when he posted a career-best seven scoreless frames. -- BS

NL East

 Atlanta Braves
After such an ascendant 2018, this season had felt like it was stuck in neutral for No. 6 Braves prospect Bryse Wilson. The 21-year-old right-hander made six appearances for Atlanta this summer but struggled to stick with a 7.20 ERA in six appearances. That said, he showed in August that he's too good for the Triple-A level as well. Wilson threw four straight quality starts for Gwinnett last month, finishing with a 1.38 ERA, 26 strikeouts and only five walks over 26 innings in August. At a time when offense was up across the board in Triple-A, Wilson's final 3.42 ERA was tops among International League qualifiers, as was his 1.26 WHIP. It's all about using Wilson's combination of plus fastball and average curve and change to find a way to get Major League hitters out repeatedly, and given his Triple-A results, he should get a few chances to figure that out in September. -- SD

 Miami Marlins
It's important to not get caught up in how a prospect performs in his Draft year, but every now and again, one takes off in a way that's worth paying close attention. Enter Peyton Burdick. The Wright State product was taken in the third round as a senior sign and showed no signs of wear with Class A Clinton, hitting .313/.435/.596 with six homers and 30 RBIs in his final 27 games with the LumberKings. It's not huge news for a college performer to dominate Class A, even this quickly, but it is notable that Burdick's power continues to play up after it took a jump this spring back on campus. Bigger tests will come in 2020, but at the very least, the Marlins' No. 29 prospect has put himself on the map more than the typical college senior would this time of year. -- SD

 New York Mets
There's a lot of hype around any first-round pick, and Brett Baty picked up a little bit of steam when the Mets moved the 12th overall selection off the complex and to Rookie Advanced Kingsport after only four games in the Gulf Coast League. However, the left-handed slugger got off to a slow start, hitting .172 as late as Aug. 15. Since that date, however, he found his footing, hitting .327/.470/.577 with eight extra-base hits and 13 walks over his final 14 games with the K-Mets. That, along with the early end to the Appy League season, prompted a move to Class A Short Season Brooklyn just in time for the New York-Penn League playoffs. There will be time to see how aggressive the Mets get with the 19-year-old going forward -- and much will depend on how MLB.com's No. 81 overall prospect can carry his above-average hit and power tools against upper-level pitching -- but his abilities to make adjustments and handle new levels this season is a promising start. -- SD

 Philadelphia Phillies
The optimism around No. 4 Phillies prospect Spencer Howard lost no momentum in August as he posted a 2.42 ERA with 28 strikeouts and seven walks over five starts (26 innings) for Double-A Reading. After missing time with a shoulder injury, Howard is back to throwing in the mid-90s and has filled the zone plenty since returning to the Fightin Phils on July 26. His stuff, which also features an above-average slider, could work in the Major League bullpen if the Phillies really decide to go for it this month, but for now, he's ticketed for the Arizona Fall League in two weeks after pitching for Reading in the Eastern League postseason. -- SD

 Washington Nationals
No. 26 Nats prospect Cole Freeman did three things very well in 2019 -- got hits, reached base and stole bags -- and that was underscored in August as he batted .338 with a .396 OBP and six stolen bases in 22 games for Class A Advanced Potomac. The 2017 fourth-rounder finished second in the Carolina League in average (.311), OBP (.394) and stolen bases (31) and fourth in OPS (.798) over 123 contests on the season. There is little power to speak of -- MLB.com grades out the tool at 20 on the 20-80 scouting scale -- but there's enough talent here, including defensive versatility as a second baseman/outfielder, to make one think Freeman could scratch out a role for himself in a Major League lineup some day. -- SD

NL Central

 Chicago Cubs
While the big league Cubs continue to chase the postseason in Illinois, the spotlight on their farm system down the stretch was on Tennessee with Nico Hoerner and Cory Abbott leading the way. Hoerner put a wrist injury further into his rear-view mirror with his best month of the season. Over his final 27 games, the No. 47 overall prospect showcased his plus-hit tool with a .321 average and his improved plate discipline with 10 walks and nine strikeouts -- both considerably better than his July stats. From the mound, Abbot led the Southern League with an 0.98 ERA and 50 strikeouts in 36 2/3 innings over six starts. With a four-pitch mix, highlighted by a cutter, the right-hander reduced his walks to nine and limited foes to a .107 average en route to being named the system's Minor League Pitcher of the Month. Johnny Cash would certainly be proud of this Tennessee Two. -- Kelsie Heneghan
Video: Tennessee's Hoerner homers

 Cincinnati Reds
Jose Garcia was having an OK first full season as he adjusted to the pitcher-friendly Florida State League. But then August came and he really busted out. The Reds' No. 9 prospect started the campaign with three straight multi-hit contests, then kept it going for a season-high 10-game hitting streak. Garcia reached based in all but three games before Class A Advanced Daytona's season was cut short on Aug. 28 due to the impending hurricane. The Cuban shortstop's .378/.426/.571 slash line was by far a career best, and he put his best tool -- his speed -- on display with seven swipes in seven attempts. Now that's ending a season a high note. -- KH

 Milwaukee Brewers
Triple-A San Antonio has played home to three of the Brewers' top position player prospects this season: Keston Hiura, Corey Ray and Trent Grisham. But Hiura was called up at the end of June and Grisham got tapped on Aug. 1 while Ray has battled injuries and slumps. Instead, Tyrone Taylor and David Freitas stepped up in big ways for the Missions. Taylor tallied a .333/.406/.564 slash line with seven of his 14 homers coming in his final 30 games of the year, showing glimpses of the high Draft pick he was in 2012. Teammate Freitas has been a star all year, following a trade from the Mariners on April 14. And after hitting .425/.494/.685 in 19 August games, the 30-year-old was called up to the Majors. Taylor and Freitas might not be the flashiest of names in the Brewers system right now, but they are certainly among the hottest. -- KH
Video: Freitas doubles in a run for PCL

 Pittsburgh Pirates
Travis Swaggerty's first full season started off strong and took a turn in May and June. But with the weather, he started heating up in July, and by August, the 2018 No. 10 overall Draft pick was scorching. In his final 27 games with Class A Advanced Bradenton, Swaggerty hit .337/.416/.490 with two homers and 10 RBIs. The speedy left-handed batter also ignited the Maruauder's run game with six swipes in eight attempts. Swaggerty finished the season fifth in the Florida State League with 57 walks while cutting down his strikeout rate from his pro debut in 2018 (25.3) to 22.1 percent. While that might not seem like much, it's a great stride in his first full season, especially given the league. -- KH
Video: Marauders' Swaggerty singles for fourth hit

 St. Louis Cardinals
Few have had more of a breakout season than Dylan Carlson, and he was sure to end the year on high note. The No. 49 overall prospect started the month with an .811 OPS in 12 games with Double-A Springfield before getting his first call to Triple-A. The 20-year-old switch-hitter kicked off his Memphis career with 18 knocks and seven RBIs over an eight-game hitting streak. Though he cooled down a tad during the remainder of the season, the tone was set. Carlson notched a .310/.385/.603 slash line over his last 30 games, spanning the two levels. But his year is not done yet. After a small break, the outfielder is taking his talents to the Arizona Fall League, where fans can continue to bask in his bat. -- KH
Video: Carlson's first Triple-A hit for Memphis

NL West

 Arizona Diamondbacks
The organization's first-round selection in June, Corbin Carroll played his way into the Northwest League, where he made his debut with Hillsboro on Aug. 8. With a 70 run grade, the outfielder immediately flashed what made him the No. 15 overall pick as he excelled in all facets of the game with the Hops. Carroll batted .326/.408/.581 over 11 NWL games during the regular season with seven extra-base hits, a pair of stolen bases and 13 runs scored. He's getting his first taste of postseason action with Hillsboro this week after turning just 19 on Aug. 11. -- RT

 Colorado Rockies
Ryan Vilade hit for average over the first four months of the season with Class A Advanced Lancaster, but not for much power. After hitting just five home runs before Aug. 1, the 2017 second-rounder smacked seven dingers in August to go with a robust .368/.412/.615 slash line for the JetHawks. In 128 games this season, the Rockies' No. 6 prospect finished with a .303/.367/.466 slash line and 12 taters over 128 games. He was fifth in the California League with 27 doubles and tied for the circuit lead with 10 triples. -- SS

 Los Angeles Dodgers
Nothing Gavin Lux has done this year could be classified as less than incredible. From Double-A Tulsa to a hotter-than-possible start with Triple-A Oklahoma City, the top Dodgers prospect eventually made his way to Chavez Ravine, where he singled in his first at-bat as a Major Leaguer. The 21-year-old continued his surge in August, hitting .319/.413/.593 in 24 games for OKC. MLB.com's No. 9 overall prospect ended his fourth Minor League campaign batting .347/.421/.607 with 59 extra-base hits, 76 RBIs and 99 runs in 113 games. Whether he ever sees a pitch in the Minors again won't be decided until next spring, but Lux clearly has nothing left to prove after arguably the finest all-around season of 2019. -- Michael Avallone

 San Diego Padres
Right-hander Luis Patiño was coming off his best month in the California League, and it earned him a promotion to Double-A Amarillo in August. In two starts with the Sod Poodles, the organization's third-ranked prospect continued to sparkle, posting a 1.17 ERA and whiffing 10 over 7 2/3 frames. In his final appearance with the club, Patiño needed just 35 pitches to navigate through three scoreless frames as he was nearly unhittable against Tulsa. However, the 19-year-old was removed from that start with a blister issue and placed on the injured list a week later, bringing his season to an end. Still, it was a promising one for the 19-year-old, who finished with 123 strikeouts over 94 2/3 innings across both levels. -- RT

 San Francisco Giants
Last August, Joey Bart was getting his feet wet in the Class A Short Season Northwest League with Salem-Keizer. Fast-forward a year later and San Francisco's top prospect is nearing what the organization hopes is a productive Major League career. Bart enjoyed a solid though injury-interrupted season with Class A Advanced San Jose, but the 22-year-old took off after his promotion to Double-A Richmond last month. The Georgia Tech product hit .316 with a .912 OPS and nine extra-base hits in 22 games for the Flying Squirrels, showing an ability to adapt after a slow start. Bart was batting .186 in his first 12 Eastern League contests but finished the season on a 17-for-36 (.472) tear that included a pair of four-hit games. -- MA