Southside Prospect Weekly: Umberger Rolls at High-A, McLain Stays Hot in Winston-Salem
By Gordon Kairis ·
Southside Prospect Weekly covers the last 7 days of action for the White Sox farm system.
Umberger's Two-Start Surge at Winston-Salem
Grant Umberger (A+, LHP, Rank: 48) put together a strong pitching week, working 12.1 innings across two starts at High-A Winston-Salem while allowing just 3 earned runs, walking one batter, and striking out 16. He generated 34 swinging misses on 178 pitches, with 87 landing for strikes. The two-start package is a meaningful statement for a 24-year-old whose season-long numbers have been uneven: the full-year ERA sits at 4.70 across 120.2 innings, with the home run rate (17 allowed) and the contact damage representing the main drag on a usable profile. This week looked nothing like that. One walk in 12-plus innings demonstrates control output that makes every average-or-better pitch play up, and 34 swinging misses in two games suggests the secondary stuff was sharp.
The recent-form arc strengthens the story. Over the last 30 days, Umberger has a 2.86 ERA in 28.1 innings, a 4.5 percent walk rate, a 27.9 percent strikeout rate, and a 34 percent whiff rate, all of which represent a meaningful step forward from his season-long marks. He is a five-pitch lefty whose carrying trait, per the scouting profile, is the ability to translate a usable left-handed arsenal into starter innings rather than one dominant put-away pitch. The curveball and changeup give him a chance to change shapes and eye levels, and when the command is working, the profile fits a back-end starter or swingman outcome. This week the command worked, and the results followed. The full-season ERA is still the headline, but a left-handed arm who can go 12.1 innings over two starts with one walk deserves attention going into the final stretch of the season.
McLain Keeps Hitting in Winston-Salem
Nick McLain (A+, OF, Rank: 38) went 7-for-17 at Winston-Salem this week with four doubles, a home run, 3 RBI, and 6 walks in 23 plate appearances. The home run was reportedly a 385-foot shot to right field, his fifth of the year and third with the Dash since his promotion. Those are not raw-power numbers, but a 23-year-old switch-hitter with a 50 hit tool and a 45 power grade whose selling point is the approach and contact foundation shows potential with a week that includes four doubles, a homer, and six walks. At High-A over the last 30 days, he is slashing with a .612 slugging mark and a .435 on-base percentage, with 4 home runs, 8 doubles, and 15 walks in 85 plate appearances. That is a month of legitimate offensive output.
The season-level split is worth tracking. McLain hit .226 at Low-A Kannapolis before the promotion to Winston-Salem, where his season line now reads .330/.462/.571. Some of that gap reflects a small sample at High-A, but the approach numbers have been consistent across both levels: an 18.1 percent walk rate for the year and a 41.3 percent swing rate that sits well below the league average. He profiles as a left-field-leaning fourth outfielder whose ceiling depends on whether the game power continues to develop or the hit tool alone has to carry him. The four-double week and the Winston-Salem stretch suggest the barrel control is translating with more authority than the 45 power grade implies. The projection is still an up-and-down role, but McLain is making the most of his shot at High-A and giving himself a real argument to push deeper into the system.
Quick Hits
- David Sandlin (AAA, RHP, Rank: 11) · struck out 11 over 5.2 innings, allowing 4 hits and 1 earned run with 1 walk and 17 swinging misses. That brings his last-30-day AAA line to a 1.88 ERA across 24 innings, with a 31.6 percent strikeout rate and a strike rate of 50.4 percent, all of it following a rough five-start stretch with the big-league club (6.93 ERA). The AAA results remain the reliable indicator of where the stuff lives: a 97-101 mph four-seamer paired with a hard slider that generates swings-and-misses in volume, with the command variance being the real separator between his Triple-A dominance and his MLB struggles.
- Alexander Albertus (A, SS, Rank: 21) · had the most productive week of any hitter in the system by counting stats per plate appearance, going 7-for-13 with a homer, a double, 7 RBI, a walk, and just 2 strikeouts in 14 plate appearances at Kannapolis. It is a continuation of a strong recent stretch: over the last 30 days at Low-A, he is hitting .366 with a 11.9 percent walk rate and a 17.9 percent strikeout rate, with an 80.1 percent contact rate. He is a 55 hit tool, 45 power player who projects as a utility infielder, but weeks like this one and a month-long contact rate above 80 percent make those grades feel like the floor rather than the ceiling.
- Javier Mogollon (A+, 2B, Rank: 32) · went 7-for-19 with a home run, a triple, a double, 5 RBI, and a walk across 19 plate appearances at Winston-Salem. The across-the-board contact this week is notable for a 20-year-old whose biggest developmental knock has been a 29.9 percent strikeout rate on the season. Over the last 30 days, that K rate has dropped to 24.4 percent while his walk rate has held at 11.8 percent, a meaningful shift for a profile built on speed (36 stolen bases this year) and emerging power. He is a utility projection, but the last month looks more like a second-division contributor in the making.
- Samuel Zavala (AA, CF, Rank: 15) · had another week defined almost entirely by patience, drawing 8 walks against 4 strikeouts in 19 plate appearances while adding just 2 hits and no extra-base knocks. No RBI, no power output, but a month-long on-base stretch that now shows a 33.3 percent walk rate and a .551 on-base percentage over his last 30 days at Birmingham. The batting average has remained low all year (.229 for the season), and the hit tool questions are real given the leg kick timing issues that can create swing-and-miss against quality velocity. Still, a left-handed outfielder who draws walks at this rate at Double-A maintains his fourth-outfield floor and keeps his ceiling conversation open.
- Junior Perez (AAA, CF, Rank: 26) · drove in 4 runs on 4 hits, including 2 home runs, in 17 plate appearances at Charlotte. It is a short but loud line for a player with plus center-field defense, a 60 arm, and a 30 hit tool that has always been the ceiling limiter. Over the last 30 days at AAA, Perez is posting a 12.8 percent walk rate and a 12 percent home run rate in his at-bats with Charlotte, showing the power-and-patience combination that keeps the bench outfielder projection alive even as the contact issues persist at a 33.3 percent strikeout rate over that stretch.
- Jaden Fauske (A, OF, Rank: 10) · had a week built entirely on patience: 2 hits but 6 walks against 4 strikeouts in 15 plate appearances at Kannapolis. No power output and no RBI, but a 22.1 percent walk rate over the last 30 days and a 34.3 percent swing rate that ranks among the most selective marks in the system. The 19-year-old has an everyday projection and a 55 hit tool, and the approach is already there. The power (.360 slugging for the season) needs to catch up before the profile fully clicks, but a teenager who controls the zone this well at Low-A gives the organization time to wait for the loft to develop.
- Tanner McDougal (AAA, RHP, Rank: 8) · had a rough week: 2.1 innings, 4 hits, 4 earned runs, 2 walks, and just 1 strikeout in 14 batters faced. It fits an ugly recent run. Over the last 30 days, his ERA at Charlotte is 11.17 across 9.2 innings, with a 21.1 percent walk rate, a 10.5 percent strikeout rate, and a strike percentage of just 37. He is a 23-year-old with a back-end starter profile, a 45 command grade, and a history of walking too many hitters, but the last month has pushed all of those concerns to the surface at once. The season-long AAA ERA is 4.53, which is still a workable number, so one rough stretch does not erase the year. But the command and the walks have to stabilize for the rotation projection to hold.
- George Wolkow (A+, OF, Rank: 18) · landed on the 7-day injured list on September 7. The specific injury has not been confirmed. He appeared in 9 games in the two weeks before the placement, going 9-for-39 with no home runs and 17 strikeouts in 44 plate appearances, a cold stretch for a player who had put together a .446 slugging mark across 557 plate appearances at Winston-Salem this year. The IL move ends what had been a full, productive High-A season (22 home runs, 15 stolen bases). Worth monitoring his status for any potential instructional league or fall work.
- Caleb Bonemer (AA, 3B, Rank: 2) · had a down week by his own considerable standard: 6-for-25 with a homer, 2 doubles, 1 RBI, 2 walks, and 5 strikeouts in 25 plate appearances at Birmingham. For context, Bonemer is slashing .263/.370/.576 over his last 30 days at Double-A, with 7 home runs, 6 doubles, and 2 triples, so a slower seven days against a .249/.378/.549 full-season backdrop with 36 home runs does not raise any real alarms. The 20-year-old third baseman still has one of the most compelling offensive profiles in the system. One softer week at Double-A does not change that.