Today's starting pitching matchup features Colorado Rockies's Michael Lorenzen (2-6, 7.03 ERA) against Arizona Diamondbacks's Zac Gallen (2-4, 4.78 ERA).

Arizona Diamondbacks's Zac Gallen posts an shaky 4.78 ERA this season, while Michael Lorenzen has been struggling at 7.03. There is a clear gap in starting pitching quality.

Advanced metrics: Michael Lorenzen — FIP 5.26, K% 15.2%, 48.7 IP / Zac Gallen — FIP 4.61, K% 15.7%, 49.0 IP

2026 season record: Colorado Rockies 20-32 (.385), Arizona Diamondbacks 26-24 (.520).

Arizona Diamondbacks holds the edge in the season standings, though Colorado Rockies can't be counted out based on head-to-head matchups.

Run differential: Colorado Rockies -54, Arizona Diamondbacks -2. Both clubs are evenly matched in run production.

Recent form: Colorado Rockies on a 1-game win streak, Arizona Diamondbacks on a 1-game losing streak.

Based on starting pitching, Arizona Diamondbacks holds the edge.

Colorado Rockies bullpen: 13 relievers on the active roster. Key arms: Antonio Senzatela 1.13 ERA, 26K in 32.0IP, Brennan Bernardino 3.72 ERA, 14K in 19.1IP.

Arizona Diamondbacks bullpen: 13 relievers on the active roster. Key arms: Brandon Pfaadt 5.61 ERA, 27K in 33.2IP, Brandyn Garcia 1.17 ERA, 7K in 7.2IP, Eduardo Rodriguez 2.24 ERA, 43K in 60.1IP.

Projected win probability: Colorado Rockies 35% vs Arizona Diamondbacks 65%

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

Workload comparison: Michael Lorenzen averages 4.9 IP per start vs. Zac Gallen at 4.9 IP. Getting six-plus innings from the starter significantly eases the bullpen burden.