Today's starting pitching matchup features Arizona Diamondbacks's Merrill Kelly (8-8, 4.86 ERA) against Cleveland Guardians's Gavin Williams (10-6, 3.71 ERA).

Cleveland Guardians's Gavin Williams posts an league-average 3.71 ERA this season, while Merrill Kelly has been shaky at 4.86. There is a clear gap in starting pitching quality.

Advanced metrics: Merrill Kelly — FIP 5.65, K% 15.0%, 109.3 IP / Gavin Williams — FIP 3.55, K% 31.6%, 133.3 IP

2026 season record: Arizona Diamondbacks 59-52 (.532), Cleveland Guardians 56-56 (.500).

Recent form: Arizona Diamondbacks on a 4-game win streak, Cleveland Guardians on a 2-game losing streak.

Based on starting pitching, Cleveland Guardians holds the edge.

Arizona Diamondbacks bullpen: 13 relievers on the active roster. Key arms: Brandon Pfaadt 4.00 ERA, 49K in 72.0IP, Brandyn Garcia (Setup) 2.10 ERA, 36K in 30.0IP, Eduardo Rodriguez 2.48 ERA, 88K in 130.2IP.

Cleveland Guardians bullpen: 13 relievers on the active roster. Key arms: Cade Smith (Closer) 2.52 ERA, 70K in 50.0IP, Colin Holderman (Setup) 1.71 ERA, 41K in 42.0IP, Erik Sabrowski (Setup) 3.77 ERA, 52K in 31.0IP.

Projected win probability: Arizona Diamondbacks 43% vs Cleveland Guardians 57%

Factors: Cleveland Guardians's starter owns the lower ERA, Cleveland Guardians's home-field advantage. Of course, baseball's inherent randomness means actual results may differ.

Workload comparison: Merrill Kelly averages 5.8 IP per start vs. Gavin Williams at 6.1 IP. Getting six-plus innings from the starter significantly eases the bullpen burden.

Merrill Kelly has allowed 22 HR this season — a concern against a lineup with extra-base power.