Prospects to Watch presented by Oak City Sports Cards: June 10-15

Keegan joins Williams, Simpson and Rock against White Sox prospects

June 4, 2025

The Durham Bulls are back home to begin their fifth homestand of the 2025 season facing off against their in-state rival Charlotte Knights, the Triple-A affiliate of the Chicago White Sox. Catcher Dominic Keegan, rated as the 12th-best Rays prospect, is joined by four others who are rated among the

The Durham Bulls are back home to begin their fifth homestand of the 2025 season facing off against their in-state rival Charlotte Knights, the Triple-A affiliate of the Chicago White Sox.

Catcher Dominic Keegan, rated as the 12th-best Rays prospect, is joined by four others who are rated among the best 30 farmhands in the Tampa Bay Rays system, including top prospect Carson Williams and speedstar Chandler Simpson, while the Knights boast seven of MLB.com's top 30 White Sox prospects, includig two of their top five in catcher Kyle Teel and infielder Colson Montgomery.

Below are the players who are currently listed for each team's Major League affiliate, with their rankings as ranked by MLB.com included.

Durham Bulls (Tampa Bay Rays Triple-A affiliate)

Williams joined the Rays out of Torrey Pines (Calif.) HS as the 28th overall pick in the 2021 Draft and didn’t need long to put his stamp on pro ball with 19 homers and 28 steals as a Carolina League All-Star for Single-A Charleston a year later. He’s been a power-speed threat ever since and was named the top prospect in the Southern League in 2024 after slashing .256/.352/.469 with 20 homers and 33 steals in 115 games for Double-A Montgomery.

On four of the five major tools alone, Williams could be a future All-Star shortstop. A Minor League Gold Glove winner, he earns praise from across the industry for his glovework at a premium position. Evaluators point out that his quickness helps him get to balls deep in the hole and his high-quality hands make sure he completes the play. He has plus-plus arm strength dating back to his days as a prep pitcher and the accuracy to go along with it. What’s more, he is strong for his size at 6-foot-2 and utilizes that with a simple setup and violent swing that gets the ball in the air.

The right-handed slugger struck out 28.5 percent of the time at Double-A last season. That’s normally a concern, but it was also down from the low 30s earlier in his career. The high K rate speaks more to pitch selection than anything mechanical; Williams tends to stay in the zone but will miss more on breaking stuff. A better understanding of swinging at more drivable pitches will keep that strikeout trend moving in the right direction and allow Williams’ plus power to play even more. But as always, his defense alone gives him a great floor as he closes in on the Majors.

Simpson might be the most intriguing player in the Minors, or at least the most unique, because of a throwback skill set that defies some modern standards for prospect evaluation. The joke before the 2022 Draft was that, on the traditional scouting scale, the former Georgia Tech infielder had 90 speed and 10 power. He hasn’t done anything to disabuse anyone of that notion, stealing 94 bases in 2023 (tied for most in the Minors) and an MiLB-leading 104 in ’24 without hitting a single home run over the fence. Will the slap-hitting speedster’s style work in the Majors? The Rays are counting on it.

There will always be concerns about Simpson’s lack of power, especially as he faces tougher pitching in the upper levels. But he’s put on some muscle in pro ball to improve his bat speed, strength and endurance, and he led all full-season Minor Leaguers with a .355 average in ’24. That’s partly a result of his speed, of course, as even a high-enough chopper -- much less a well-placed bunt -- can easily turn into an infield hit. But it’s also a product of his feel for the strike zone and ability to make contact, as he had more walks (44) than strikeouts (43) in High-A and Double-A last year. Plus, his top-of-the-scale speed effectively allows him to turn his walks and singles into doubles or triples.

As perhaps the fastest man in baseball, Simpson will be held to a high standard defensively -- one he may not yet meet entering only his third full season as an outfielder. Primarily a second baseman in college, Simpson is still learning the nuances of center field. That may occasionally be evident in the form of bad jumps of misread balls, offering a reminder that not every 80-grade runner is an 80-grade outfielder. But he has improved over time and shown a desire to keep getting better, a sign of his plus makeup, and his speed can cover a lot of mistakes in the outfield. At worst, he’ll reach the Majors and be must-see TV anytime he’s on base. If he puts it all together, he could be a high-average hitter with unmatched basestealing ability and an impactful defender at a premium position.

Seymour took an unusual path to the Rays’ 40-man roster, having gone undrafted out of high school before being selected in the second round of the 2020 Draft out of Virginia Tech following three strong seasons and a notable performance in the Cape Cod League. Flexor soreness kept him off the mound until July 2021, but then he flew through the system by posting a 1.95 ERA with 87 strikeouts in 55 1/3 innings over 14 outings from High-A to Triple-A. The big league staff had even taken notice of Seymour’s work by the end of that season, but his hurried ascent was stalled when he underwent Tommy John surgery in June 2022. He worked his way back to the mound in ’23 then pitched his way back onto the radar in ’24, logging a 2.35 ERA and 0.95 WHIP in 27 starts between Double-A and Triple-A.

Seymour has a deep arsenal, headlined by a filthy changeup that generated a 45.5% whiff rate during 10 Triple-A outings last season. His fastball velocity sits in the low-90s, but everything he throws plays up due to his deceptive delivery and strike-throwing ability. Throughout his time in the Minors, Seymour has averaged 11 strikeouts and 3.1 walks per nine innings. The lefty leans on his fastball and changeup but also makes use of an effective cutter, a slider and the occasional curveball.

Having proven his health and his return to pre-surgery form, with nothing but success behind him in the Minors, Seymour seems likely to play a role for the Rays this season as a starter or a bulk-innings reliever, someone who can turn over a lineup multiple times by relying on his varied pitch mix. He may not be suited for traditional lefty relief work considering his changeup is his best offspeed pitch, but he’s bound to pitch his way into the big leagues soon enough.

Keegan will turn 25 in August, but he’s still relatively young in his life as a frontline backstop. He was a backup catcher at Vanderbilt during the Commodores’ run to the 2019 College World Series, spent most of his time at first base in 2020-21 and worked evenly at both spots during his senior season in ’22. The Yankees selected him in the 19th round of the 2021 Draft, and the Rays were intrigued enough by his offensive and defensive upside to spend a fourth-round pick (and a $397,500 bonus) on him a year later.

Since his 2021 breakthrough at Vandy, Keegan has consistently hit. The idea of having a catcher with his natural hitting ability is intriguing, especially for a club like the Rays that has often been starved for offense behind the plate. He has an easy right-handed swing, with decent power to all fields. The Rays pushed him to Double-A in 2024 after only 48 games in High-A the year before, and he responded by batting .285/.371/.435. He’s consistently struck out in about 20 percent of his plate appearances while pushing double-digit walk rates. He’s not necessarily a star hitter, with modest home run totals and limited baserunning value, but what he can do at the plate as a catcher is still his strength.

There are still concerns about Keegan’s defensive ability, and one wonders if a team like the Rays -- who have often prioritized defense behind the plate to the detriment of their lineup -- will ever count on him as a frontline catcher. But he is smart and cerebral, a good game-caller and a roughly average defender overall who’s shown continual improvement with the desire for more. His framing in some parts of the zone, including his glove side, could stand to improve. He has a strong arm but not necessarily a shutdown cannon. The Rays think he’ll be firmly above-average defensively with more reps, but at worst, he has a big league future as an offensive-minded catcher.

Joe Rock, LHP - #22 Rays prospect
Scouting grades: Fastball: 55 | Slider: 55 | Changeup: 50 | Control: 45 | Overall: 40

Undrafted out of high school, Rock used an excellent junior season at Ohio University as a springboard into the Draft and wound up being selected by the Rockies in Competitive Balance Round B of the 2021 Draft. He pitched most of 2022 in High-A before getting a brief taste of Double-A, then repeated that pattern in 2023. Then, just as he wondered if he was on the brink of the big leagues, he was shipped from the Rockies to the Rays in March 2024 for 2019 first-round pick Greg Jones. Rock then spent the whole season in Triple-A, posting a 4.58 ERA over 27 outings, before being added to Tampa Bay’s 40-man roster.

When Rock is on, he can look like a lights-out, sure-thing starter. He has three solid pitches, starting with a fastball that averages around 92 mph but can reach up to 94-95 mph, coming from a slightly lower slot that can make it hard for hitters to pick up the ball. Standing at 6-foot-6 with long limbs, he also gets great extension on all his pitches. He has reworked his slider since last year, looking to add velocity to his primary breaking pitch. He also throws a changeup that can be effective against right-handers.

After a full season in Triple-A, Rock is clearly close to joining the Major League staff. He may never have pinpoint command, given his long limbs and unorthodox delivery. But even if he doesn’t reach his ceiling as a starter, it’s not hard to imagine the Rays shortening him up and letting him unleash fastballs and sliders as a left-handed reliever.

Charlotte Knights (Chicago White Sox Triple-A affiliate)

Teel rated as one of the top prep catchers in the 2020 Draft and could have gone in the first three rounds had he not withdrawn because he wanted to attend Virginia. He developed into the best backstop in the 2023 Draft after three years with the Cavaliers, winning Atlantic Coast Conference player of the year honors that spring before surprisingly falling to the Red Sox at No. 14. He reached Double-A at the end of his pro debut and Triple-A by the end of 2024, then went to the White Sox as the best of four prospects traded for Garrett Crochet at the Winter Meetings in December.

Teel has a sound left-handed swing, a disciplined approach and a higher offensive ceiling than most catchers. He uses the entire field, with most of his home run power going to his pull side. He should hit for average while drawing plenty of walks and providing 15-20 homers per year.

More athletic but less physical than most at his position, Teel has present average speed but will slow some as he spends more time behind the plate. He struggled at times with his receiving and blocking during his first full pro season, but he also made progress during the year and should be at least an average defender. He has solid arm strength with a quick transfer and makes accurate throws.

Montgomery set the career scoring record at Southridge HS (Huntingburg, Ind.) with 1,966 points on the basketball court and Indiana offered him the chance to walk on its hoops team if he attended college on a baseball scholarship. That didn't happen because he went 22nd overall in the 2021 Draft and signed for $3,027,000. He has risen swiftly through the White Sox system but struggled for much of 2024 at Triple-A, where he slashed .214/.329/.381 with 18 homers in 130 games at age 22.

Because he's a physical lefty-hitting shortstop, Montgomery has drawn constant comparisons to Corey Seager, and he showed similar power and hitting ability at the lower levels of the Minors. But Montgomery's approach has changed in the past two years, when he has become much more focused on launching balls in the air to his pull side, and his swing decisions regressed last season as his chase rate jumped to 30 percent from 17 percent in 2023. He still has 30-homer pop and draws his share of walks, but he's a career .253 hitter through his first four years as a pro.

Montgomery exhibits below-average speed out of the batter's box but is an average runner once he gets going, albeit not much of a threat to steal. He moves well at shortstop, making plays with a quick first step, good agility for his size, a fine internal clock and solid arm strength. Chicago believes he'll stay at shortstop despite his size, while some scouts think he could be a plus defender at third base, where he spent most of his two-week Arizona Fall League stint in October.

Jairo Iriarte, RHP - #7 White Sox prospect
Scouting grades: Fastball: 55 | Slider: 55 | Changeup: 55 | Control: 45 | Overall: 45

Signed for $75,000 out of Venezuela in 2018, Iriarte blossomed into one of the best arms in the Padres system and was pushing for a big league promotion as a 21-year-old in 2023. After the White Sox acquired him in a three-prospect package for Dylan Cease in March 2024, he ranked third in the Double-A Southern League in opponent average (.228) and WHIP (1.28) and fourth in ERA (3.71) and strikeouts (122 in 126 innings). He posted a 1.50 ERA in six relief appearances with Chicago at the end of the season.

After parking in the mid-90s and peaking at 100 mph in the first half of 2023, Iriarte's fastball has settled in at 92-94 mph with a high of 96, and its excessive armside run now stands out more than its velocity. His sharp 82-85 mph slider has good horizontal action in the opposite direction and plays well off his heater. So does his upper-80s changeup with fade, giving him a third solid offering.

While Iriarte wasn't as overpowering as the year before he did throw more strikes, though his control and command still need more work. He's athletic and creates plenty of extension with his delivery, adding to his deception. He could be a No. 3 starter if he improves his location, perhaps more if he recaptures some velocity, but he also could wind up as a late-inning reliever.

Gonzalez signed for $250,000 out of Venezuela in 2018 and became the Red Sox's best pitching prospect five years later, when he led the Minors in strikeout rate (13.6 per nine innings) and percentage (35 percent). His 2024 was a tale of two halves, as he recorded a 7.94 ERA and .756 opponent OPS in his first 12 Double-A outings versus a 1.84 ERA and .471 opponent OPS in his final dozen. If he can find more consistency, he could be a steal as the lowest-ranked of the four prospect the White Sox acquired from Boston in the Garrett Crochet trade at the Winter Meetings in December.

After initially struggling to make mechanical adjustments designed to help his control in 2024, Gonzalez regained his fastball velocity by the end of the season, working at 94-96 mph and reaching 99 with difficult carry and run coming out of a flat approach angle. All three of his secondary pitches can grade as plus at their best but lack reliability, and the best of them is an upper-70s curveball with downer break when he stays on top of it. His fading mid-80s changeup is better than his tight slider with similar velocity.

Gonzalez creates tremendous extension with his athleticism and mobility, allowing his pitches to get on hitters much quicker than they realize. He also has effort in his delivery that hampers his fastball command and his ability to land his breaking pitches for strikes. There's a lot of variance in what he might evolve into, as he has the upside of a mid-rotation starter but the floor of a reliever who lacks the control for high-leverage situations.

Schweitzer won Mid-American Conference pitcher of the year accolades after ranking second in NCAA Division I with 11 victories in 2022. He followed future big leaguers Drey Jameson, Kyle Nicolas and Chayce McDermott to give Ball State its fourth top-five-round pitcher in five Drafts when the White Sox popped him in the fifth round that July. One of the most consistent starters in the system, he logged a 4.02 ERA with a 136/41 K/BB ratio in 132 innings between High-A and Double-A last year.

After his fastball operated around 90 mph in college, Schweitzer has gotten stronger and now sits at 91-93 with a high of 96, and it plays up thanks to high spin rates that create carry. His slider also has gotten hotter, averaging 84 mph last year compared to 79 mph in 2022, and flashes as a solid offering with two-plane depth at times. He keeps hitters off balance by mixing in an upper-70s curveball and a too-firm changeup in the mid-80s with more downhill plane than life.

Schweitzer walks a fine line by throwing consistent strikes without catching too much of the plate with his decidedly average stuff. He mixes his offerings and locations well, giving him the chance to crack the back of a big league rotation. He's not very physical but has proven very durable and efficient in three years as a college and pro starter.

Nastrini's control woes got him bounced from UCLA's rotation early in his 2021 junior season, but the Dodgers thought they could help him and took him in the fourth round after he performed well in a pre-Draft workout and summer ball. They helped him harness his impressive stuff and turned him into one of their better pitching prospects before packaging him a trade for Lance Lynn and Joe Kelly in July 2023. His arsenal and ability to locate it regressed in his first full season in the White Sox organization, which included going 0-7 with a 7.07 ERA in nine big league appearances.

Nastrini operated with a 92-95 mph fastball and topped out at 97 in 2024, down a tick from earlier in his pro career, mitigating a lack of armside run with considerable carry. His best pitch is a tight mid-80s slider that reaches 89 mph with high spin rates, though it also was responsible for 11 of his 24 homers allowed last season. He also throws a solid upper-70s curveball and an average mid-80s fading changeup but has trouble landing both for strikes.

Though Nastrini's fastball, curve and slider all can grade as at least plus when they're on, they also can get hammered if he doesn't place them well. His walk rate jumped from 11 percent in his first three years as a pro to 16 percent in 2024, and his command also went backward. The rebuilding White Sox can afford him more chances as a starter, but he's looking more and more like a long-term reliever.

Pallette was pitching his way toward the first round of the 2022 Draft before he injured his elbow in May the year before. He tried to rehab the injury but wound up having Tommy John surgery in January 2022, missed his junior season at Arkansas and signed for an over-slot $1.5 million as a second-rounder. He regained his stuff but struggled with his consistency in his first 1 1/2 pro seasons, then found more success after the White Sox moved him to the bullpen last July.

Pallette works at 94-96 mph and touches 98 with high spin rates on his fastball. He can produce upward of 3,000 rpm on his low-80s downer curveball, but it breaks so much that he has trouble landing it in the zone or getting chases. He still uses four pitches as a reliever, and his changeup and slider both arrive in the mid-80s and grade as average offerings.

Because he's not especially tall and has an upright delivery, Pallette creates more downhill plane than extension, so he needs to command his fastball up in the zone to be effective. He's throwing more strikes as a reliever than he did as a starter, and he looks like a potential setup man. Once he harnesses his curveball more regularly, he'll be ready for the call to Chicago.