Stock Watch: First-Half All-Risers team

Midseason prospect lists are rolling out across the internet, and with the baseball world taking a collective deep breath this week in preparation for the second half, it seems like a good time to reflect back on the season to date.

With that in mind, here's a rundown of the players who have done the most to move the needle on their prospect stock this season. Note that this isn't a list of top prospects at each position, but rather, players listed have made the biggest jump from the start of the season.

Catcher

Jacob Nottingham, Houston Astros, Class A Advanced Lancaster

Perhaps no prospect on this list has taken a bigger leap forward than Nottingham, who was basically an unknown prior to his breakout performance this year. Currently No. 22 among Astros prospects according to MLB.com, Nottingham should get a massive jump up when those rankings are shuffled. The backstop is a physical specimen who could have played Division I college football. At the plate, he boasts a .335/.393/.573 line across two levels this year, showing a powerful stroke and developing approach. Behind it, he still has a long development road ahead, but the requisite athleticism and makeup are there to suggest Nottingham can close the gap and become an average defender or better. An above-average hitter with average defense at catcher is a hugely valuable asset, and that's what Houston might have in Nottingham.

Honorable mention: Willson Contreras (Cubs)

First Base

Cody Bellinger, Los Angeles Dodgers, Class A Advanced Rancho Cucamonga

What we knew about Bellinger before the season was that he could really defend at first and that he had solid bat-to-ball skills. What we were unsure of was the power. Playing the first half at just 19 years old, Bellinger has offered a resounding answer to the questions about his pop. His 16 home runs are no California League mirage -- the left-handed hitter is mashing balls over the right-center gap with regularity, producing an .807 OPS as one of the youngest players at Class A Advanced. He's also showed some promise in the outfield, putting positional flexibility on his side. Bellinger should easily fall among the top 10 Dodgers prospects when MLB.com re-ranks this month and could threaten the Top 100 list. 

Honorable Mentions: Balbino Fuenmayor (Royals), Trey Mancini (Orioles), A.J. Reed (Astros), Jake Bauers (Rays), Bobby Bradley (Indians), Ryan O'Hearn (Royals)

Second base

Jacob Wilson, St. Louis Cardinals, Triple-A Springfield

Wilson was looking like a breakout performer in St. Louis' system last year before injury limited him to 66 games between Class A Advanced and Double-A. He returned to Double-A to start this season and quickly advanced to the Pacific Coast League, where he's emerged as a slugging right-handed hitter capable of playing second and third base at a Major League level. Wilson's overall numbers -- a .240/.319/.461 line with 15 homers -- have been held back by poor batted-ball luck, though Wilson's propensity for hitting fly balls will likely always lead to suppressed batting averages on balls in play. Wilson may be just a .250 hitter in the Majors, but he could also hit 20-plus home runs annually, giving him a statistical profile potentially similar to Brian Dozier, who was worth 4.8 Wins Above Replacement last year, per Fangraphs.

Honorable mentions: Tony Kemp (Astros), Mauricio Dubon (Red Sox)

Shortstop

Javier Guerra, Boston Red Sox, Class A Greenville

Evaluators knew Guerra could play shortstop coming into the year. The real question regarding the 19-year-old Panamanian was how well he could hit. The Drive are loaded with talented bats this season, and Guerra has kept pace with all of them, hitting .298 with an .853 OPS. The biggest surprise has been his power. Guerra is listed at 155 pounds, although Greenville manager Darren Fenster told MiLB.com he's likely heavier and stronger than that now. The power numbers back Fenster's claim, since Guerra leads the team with 11 home runs in 70 games. Guerra could be an average hitter with average pop and outstanding defense at shortstop, which would make him a perennial All-Star up the middle. A number of shortstops have taken massive steps forward this year -- Orlando Arcia and Ruddy Giron particularly stand out among the honorable mentions -- but Guerra's rise from back-end Top 20 Red Sox prospect to Top 100 candidate gets the nod for the biggest jump.

Honorable mentions: Trevor Story (Rockies), Orlando Arcia (Brewers), Trea Turner (Nationals), Ozzie Albies (Braves), Gleyber Torres (Cubs), Jorge Mateo (Yankees), Ruddy Giron (Padres), Malquin Canelo (Phillies)

Third Base

Richie Shaffer, Tampa Bay Rays, Triple-A Durham

Shaffer was profiled in these pages last week for the dramatic steps he's taken offensively. The 24-year-old has already blown past his previous career high with 21 home runs across two levels, and he hasn't slowed since a jump to the International League. He's slugging an outrageous .657 in 38 games with the Bulls, bashing fly ball after fly ball over the left-field fence. Shaffer brings average defense to third base and is suddenly showing 25-plus homer potential after tweaking his swing and adding 25 pounds of muscle last offseason. Shaffer was listed in the back half of the Rays' Top 30 list coming into the season but could get some Top 100 buzz by year's end -- if he's not already in the Majors -- which helps him narrowly edge out Rafael Devers for honors here.

Honorable mentions: Rafael Devers (Red Sox), Jomar Reyes (Orioles)

Outfield

Nick Williams, Texas Rangers, Double-A Frisco

Williams has long boasted one of the highest offensive ceilings among all prospects due to his lightning-quick hands -- some, including Williams himself, think they're the fastest in the Minors. This year, he's taken a crucial step toward approaching that ceiling by drastically improving his plate approach. Last year, he struck out in 28.7 percent of his plate appearances with Class A Advanced Myrtle Beach. This year, Texas jumped Williams to Double-A, and despite the uptick in competition, he's slimmed his whiff rate all the way down to 18 percent while also drawing more walks and still hitting for above-average power. Overall, Williams has a .295/.354/.455 line with nine homers in 83 games with the RoughRiders. 

Bradley Zimmer, Cleveland Indians, Double-A Akron

Zimmer was one of the bigger names among the college bats in the 2014 Draft class but slid all the way to the 21st pick in part because of concerns that he had a tweener profile -- not enough range for center field, and not enough power for a corner. A year later, Zimmer appears to be one of the biggest steals from the that Draft. Range and speed are no longer a problem -- he's receiving solid reviews for his work in center and has also stolen 32 bases in 37 tries with Class A Advanced Lynchburg. He's also shown plenty of power, slugging 10 homers and posting a .182 isolate power with the Hillcats prior to a promotion to Double-A earlier this week.

Brett Phillips, Houston Astros, Double-A Corpus Christi

The 21-year-old bashed his way onto the prospect scene last year with an .883 OPS for Class A Quad Cities. This year, he's cemented his place as one of the game's most exciting outfield prospects. Phillips has gotten faster as a pro and now has the range to play center along not to mention probably the strongest arm in Houston's farm system. At the plate, he has a solid approach and should hit for average and power, and he can steal some bases, too. Phillips is a five-tool player who is getting his due from evaluators and prospect outlets -- Baseball America ranked him 21st overall on their midseason Top 50 list, and it wouldn't be surprising if others offer similar praise in the near future.

Honorable mentions: Billy McKinney (Cubs), Max Kepler (Twins), Manuel Margot (Red Sox), Carlos Tocci (Phillies), Anthony Alford (Blue Jays)

Right-handed starting pitcher

Jose De Leon, Los Angeles Dodgers, Double-A Tulsa

De Leon came into the year with a whole lot of prospect buzz after showing a big velocity spike in 2014, but most evaluators were still taking a wait-and-see approach to make sure the 22-year-old's improvements were for real. Now, the baseball world is fully on board. De Leon has replicated the velocity and emerged as one of the game's top pitching prospects. He pummels the strike zone with mid-90s heat, keeps hitters off the fastball with a changeup and slider and does it all with an innate ability to deceive hitters. His 122 strikeouts lead the Minors by a massive margin -- the Angels' Sean Newcomb is second with 106 -- and the scouting reports back the numbers.

Honorable mentions: Jeff Hoffman (Blue Jays), Alex Reyes (Cardinals), Brent Honeywell (Rays), Michael Kopech (Red Sox)

Left-handed starting pitcher

Blake Snell, Tampa Bay Rays, Double-A Montgomery

Snell has boasted frontline stuff since Tampa Bay selected him 52nd overall in the 2011 Draft, but his command and concentration both wavered early in his career. This year, Snell has matured and sharpened his focus, gaining better control of his repertoire in the process. Snell opened the season with 46 consecutive scoreless innings and has been dominant even since the streak ended. In 15 appearances (13 starts) across two levels, he has a 1.28 ERA with 99 strikeouts in 84 2/3 innings. His control is still subpar, but his 3.96 walks per nine innings in Double-A is his lowest rate since Rookie ball. If he can continue to shrink that number, he could compete for a spot in the Rays' rotation at some point in the next few seasons.

Honorable mentions: Brian Johnson (Red Sox), Amir Garrett (Reds), Stephen Gonsalves (Twins)

Falling for injury

Orioles RHP Dylan Bundy: It looked like Bundy had turned the corner in his return from Tommy John surgery, since his velocity and command were sharper in Spring Training than in 2014. His comeback was put on hold by shoulder inflammation, though, and now the righty is likely done until at least the Arizona Fall League.

Pirates RHP Jameson Taillon: The right-hander missed all of 2014 with Tommy John surgery. He was on his way back to game action this year, but will be out until at least September after undergoing hernia surgery last week.

Rangers C Jorge Alfaro: Perhaps no prospect on MLB.com's Top 100 needed reps more than Alfaro, who is supremely athletic but lacked polish on both sides of the ball and especially behind the plate. An ankle injury will likely keep Alfaro sidelined for the rest of 2015.

Falling for performance

Marlins RHP Tyler Kolek: Kolek still has a chance to develop into a frontline starter, but he's lost steam since going second overall to Miami in the 2014 Draft. Pitching with Class A Greensboro, the 19-year-old has struck out just 45 batters in 71 innings while walking 32. His stuff -- which included a triple-digit fastball -- has regressed a bit in full-season ball, and his control has a long way to go, as well. Those things are fixable, and it's far too soon to jump ship on the 6-foot-5 Texan, but you have to think Miami would rather have Carlos Rodon -- the No. 3 pick in last year's Draft -- or one of the other players they passed on when selecting Kolek last season.

Red Sox LHP Henry Owens: The 6-foot-6 southpaw has had his control waver in the past, but he's always recovered after a few shaky starts. He's been slower to rebound this year, walking 52 over 104 1/3 innings with Triple-A Pawtucket. He's been sharper of late, but has fallen behind the likes of Eduardo Rodriguez and Brian Johnson, who have advanced past Owens to the Majors this year.

Twins RHP Alex Meyer: Meyer is in the Majors, so the worst-case scenario has been avoided here, but he's also there as a reliever, which has to be a disappointment for Twins fans who hoped Meyer could bring his command and changeup along enough to stick in the rotation. Alas, Minnesota will have to settle for a lights-out bullpen arm, which is still a nifty asset.