Chicago Cubs vs. Arizona Diamondbacks Prediction – August 25, 2026
The Chicago Cubs make the trip to Chase Field to take on the Arizona Diamondbacks in what projects to be a competitive Tuesday night affair. WP Baseball Predictor has crunched the numbers and is siding with the Diamondbacks at +1.5 on the run line, even as the model gives the Cubs a slight edge in outright win probability. Here is everything you need to know before first pitch.
Starting Pitcher Matchup: Holmes vs. Pfaadt
The pitching matchup sits at the center of this preview, and the metrics point to a meaningful edge for the Cubs on the mound. Chicago will send Clay Holmes to the bump, who carries an xFIP of 3.52 — a mark that indicates he has been limiting hard contact and suppressing expected run output at an elite level this season.
Arizona counters with Brandon Pfaadt, who owns an xFIP of 4.07. While Pfaadt is a capable arm and a known commodity in the National League, that half-run gap in expected fielding-independent pitching between the two starters is significant. Holmes's superior xFIP suggests he is the more reliable bet to keep opposing hitters off the board on a per-plate-appearance basis, and that discrepancy is a key driver behind the Cubs' 57.3% outright win probability in the model.
In short, if Holmes brings his best stuff to Chase Field, the Cubs' lineup should be well-positioned to outscore Arizona's offense.
Why WP's Model Favours the Diamondbacks +1.5
At first glance, it may seem contradictory that WP Baseball Predictor picks the Diamondbacks at +1.5 while simultaneously assigning the Cubs a 57.3% win probability against Arizona's 42.7%. The logic lies in the run-line value. The Cubs are not listed as a strong favourite, meaning the model does not project a blowout outcome. In close contests, the run line offers meaningful cushion. Arizona only needs to either win outright or lose by a single run to cash the +1.5, and in a game where neither team is heavily favoured, that extra run of protection carries real value.
Supporting Arizona's case offensively, the Cubs' team FIP sits at 4.74 — the highest of the two pitching staffs — suggesting Chicago's bullpen could be a vulnerability if Holmes departs early. The Diamondbacks' team FIP of 4.49 is modestly better, adding a slight layer of relief-pitching confidence for Arizona.
Injury Report: Key Absences to Monitor
Both rosters are dealing with notable injury attrition heading into this matchup.
Cubs Injuries
- Edward Cabrera – Finger (15-Day IL)
- Gavin Hollowell – Shoulder (15-Day IL)
- Corbin Martin – Undisclosed (7-Day IL)
- Hoby Milner – Abdomen (15-Day IL)
- Matt Shaw – Hand (10-Day IL)
The Cubs are missing multiple bullpen arms, including Milner and Hollowell. Bullpen depth is always critical when protecting a lead, and Chicago's relief options could be stretched thin if Holmes is asked to exit before the seventh inning.
Diamondbacks Injuries
- Ketel Marte – Knee (10-Day IL)
- Lourdes Gurriel – Thigh (10-Day IL)
- Yordin Chalas – Undisclosed (7-Day IL)
- Aramis Garcia – Undisclosed (7-Day IL)
- Modeifi Marte – Undisclosed (7-Day IL)
Arizona's most impactful absence is Ketel Marte, one of the Diamondbacks' most dangerous offensive threats. His absence from the lineup meaningfully reduces Arizona's ceiling at the plate and is a factor behind the team's wOBA of 0.311 — noticeably lower than the Cubs' 0.332 mark.
Dark Horse Home Run Picks
Cubs: Michael Conforto
With the Cubs posting the stronger team wOBA and Pfaadt carrying an xFIP north of 4.00, veteran outfielder Michael Conforto is well-positioned to do damage. Keep an eye on him as a sneaky power threat in this matchup.
Diamondbacks: Corbin Carroll
Despite Arizona's offensive limitations tonight, Corbin Carroll always carries home run upside and remains one of the most dangerous individual hitters in the Diamondbacks' lineup. At home at Chase Field, he is never someone you want to sleep on.
Final Prediction
The WP Baseball Predictor model gives the Cubs a 57.3% outright win probability behind Clay Holmes's strong xFIP advantage over Pfaadt. However, given the thin margin between these clubs and Chicago's bullpen injury concerns, Arizona +1.5 represents the sharp play. Expect a close, competitive game decided late.
WP Pick: Diamondbacks +1.5