Chicago White Sox @ St. Louis Cardinals Prediction – September 12, 2026
As the 2026 MLB season enters its final stretch, the Chicago White Sox travel to St. Louis to take on the Cardinals in what projects to be a competitive, evenly matched late-season affair. The WP Baseball Predictor has issued a Slight Lean toward the Cardinals +1.5, signaling a close game where the run line offers meaningful value. Here's a full breakdown of everything shaping this matchup.
Starting Pitcher Matchup: Newcomb vs. Leahy
The pitching duel at the heart of this game features two arms whose underlying metrics suggest a genuinely competitive contest, though one holds a clear edge on paper.
Sean Newcomb (Chicago White Sox)
Newcomb takes the mound for Chicago carrying an impressive xFIP of 3.00, which is among the stronger marks you'll find from any starting pitcher this deep in the season. xFIP strips away the noise of defense and luck to measure how a pitcher is truly performing, and Newcomb's number indicates he has been limiting hard contact and keeping hitters off-balance at an elite level. He enters this start as arguably the most intriguing pitching storyline of the game.
Kyle Leahy (St. Louis Cardinals)
Leahy counters for St. Louis with an xFIP of 3.65. While that figure is less sharp than Newcomb's, it still represents a respectable profile for a home starter. The gap between the two arms — 0.65 points of xFIP — is notable and gives Chicago a clear advantage in the individual pitching matchup. However, the WP model's team-level analysis clearly accounts for more than just starting pitcher metrics.
Why the WP Model Favors the Cardinals +1.5
Despite Newcomb's superior xFIP, the WP Baseball Predictor's Slight Lean lands on the Cardinals +1.5. Understanding why requires a look at the full team-level picture.
On the pitching side, St. Louis carries a team FIP of 4.17 compared to Chicago's team FIP of 4.34, suggesting the Cardinals' pitching staff as a whole has been the more efficient unit throughout the season. The Cardinals also own a slightly lower team ERA of 4.3 versus the White Sox's 4.15, though that gap is narrow enough to be largely inconsequential.
Offensively, Chicago holds a modest edge with a team wOBA of 0.315 against St. Louis's 0.307, meaning the White Sox have been the slightly more productive offensive club. Still, the Cardinals' superior bullpen and overall pitching depth appear to be driving the model's lean. The run line pick of +1.5 further reflects the expectation of a close, competitive game where St. Louis has the structural advantages to hold their own even if they trail.
Injury Report: Key Absences to Monitor
Both rosters are dealing with notable absences that could influence lineup construction and late-game options.
Chicago White Sox Injuries
- Joey Bart (Hand, 10-Day IL) – Losing a catcher disrupts game-planning and pitch sequencing against an unfamiliar opponent.
- Tommy Pham (Calf, 10-Day IL) – An experienced bat removed from the lineup weakens Chicago's offensive depth.
- Huascar Brazoban (Lat, 15-Day IL), Billy Carlson (Out), Roch Cholowsky (Wrist, Out) – Bullpen and roster depth are thinned considerably heading into this game.
St. Louis Cardinals Injuries
- Blaze Jordan (Ankle, 10-Day IL) – A power bat sidelined limits St. Louis's lineup versatility.
- JJ Wetherholt (Wrist, 10-Day IL) and Everson Pereira (Hand, 10-Day IL) – Two additional offensive contributors unavailable.
- Hunter Dobbins (Elbow, 15-Day IL) and Peter Strzelecki (Forearm, 15-Day IL) – Relief depth for St. Louis is also compromised.
Both teams are navigating thin rosters, but Chicago's injury list may have a broader offensive impact given the absence of Pham and Bart.
Dark Horse Home Run Picks
Every late-season game carries the potential for an unlikely hero to emerge. Here are two players worth watching for a surprise long ball.
Randal Grichuk (Chicago White Sox)
Grichuk is a veteran outfielder with legitimate power capability who can make pitchers pay when he gets a pitch to drive. With Chicago missing pieces in the lineup, Grichuk could see favorable counts and elevated opportunities that make him a legitimate dark horse HR threat against Leahy.
Joshua Báez (St. Louis Cardinals)
Báez is an intriguing young Cardinal who possesses the raw power to go deep on any given night. Playing at home with crowd support behind him, Báez could make an impact against Newcomb if he finds his pitch early in the at-bat.
Final Prediction
This matchup is too close to call with confidence, which is precisely why the WP Baseball Predictor registers only a Slight Lean rather than a stronger signal. Newcomb's elite xFIP gives Chicago a real shot at keeping this game tight, but the Cardinals' superior team-level pitching metrics and home-field environment tip the scale just enough. Cardinals +1.5 is the WP pick — expect a low-scoring, competitive game that could easily go either way.