The Arizona Diamondbacks wrap up a late-season road trip with a Wednesday night matchup against the Colorado Rockies at Coors Field, first pitch set for 8:40 PM ET on September 23, 2026. Merrill Kelly takes the ball for Arizona against Colorado's Mason Adams in what shapes up as a pivotal regular-season contest. Coors Field is never a neutral environment — the altitude and thin air inflate offensive numbers for both sides — and that reality makes Kelly's assignment one of the tougher asks any D-backs starter will face all year. Arizona fans can catch the action on DBACKS.TV or Arizona Sports 98.7 FM.

Pitching Matchup: Merrill Kelly vs. Mason Adams

Merrill Kelly is the known commodity in this equation. A veteran right-hander who has been a reliable innings-eater and competitive presence in the Arizona rotation, Kelly's ability to command the strike zone and generate soft contact will be tested by Coors Field's unforgiving dimensions. Keeping the ball on the ground and limiting the big inning will be every bit as important as his pure stuff Wednesday night.

On the other side, Mason Adams gets the start for Colorado. Adams is a younger arm in the Rockies' system, and this late-season opportunity against a legitimate opponent is a chance for him to show what he can do. The D-backs will look to attack Adams early, force pitch counts up, and get into the Colorado bullpen before the game gets away from them.

Colorado Rockies Starting Lineup

• Jake McCarthy — DH
• Cole Carrigg — CF
• Hunter Goodman — C
• TJ Rumfield — 1B
• Kyle Karros — 3B
• Adael Amador — 2B
• Mickey Moniak — RF
• Zac Veen — LF
• Ezequiel Tovar — SS

Keys to Watch for Arizona

Keep the Ball in the Park

This sounds obvious at Coors Field, but it bears repeating. The ballpark inflates run totals across the board. Kelly's success Wednesday night will hinge on limiting hard contact and keeping fly balls from carrying over the fences. Any pitcher who loses command at altitude pays for it quickly.

Get After Adams Early

The D-backs' lineup needs to be aggressive against Adams. Force him to work deep counts, get runners on base in the first two innings, and make Colorado's bullpen pitch as many innings as possible. The Rockies' late-inning relief options are not a group Arizona should fear if it can get there.

Road Discipline Matters

Coors Field road games have a way of turning into high-scoring slugfests that punish the team that falls behind. Arizona's offense needs to score first or respond quickly if Colorado jumps ahead — playing from behind at altitude is a difficult position for any club.

Prediction

Coors Field is a wild card every single time, and Kelly will need to be at his sharpest to navigate the conditions. Adams is an unknown who could either struggle against a veteran lineup or hold Arizona in check through the middle innings. This one has the feel of a game that stays competitive until the sixth or seventh inning before the bullpens take over and the run totals climb. Give the edge to Arizona based on the experience Kelly brings to the mound — D-backs 7, Rockies 5.