Diamondbacks vs. Rockies Prediction, Odds, Probable Pitchers, Prop Bets for Wednesday, Sept. 23

The Arizona Diamondbacks are four games out of a playoff spot in the National League heading into Wednesday’s matchup with the Colorado Rockies – the worst team in MLB.

Arizona took Game 1 of this series on Tuesday, and it has won three games in a row to stay alive with San Diego, Chicago and Philadelphia all tied right now in the wild card race. That gives the D-Backs three potential teams to catch, but they need at least one of those teams to lose quite a bit over the final few days of the regular season.

On Wednesday, the D-Backs have Merrill Kelly (5.00 ERA) on the mound against Colorado’s Mason Adams (5.09 ERA), who is making his sixth appearance of the season. Oddsmakers have set the D-Backs as road favorites against a Rockies team that hit the 100-loss mark on Tuesday night.

Let’s take a look at the odds, a player prop to bet and my prediction for this NL West clash on Wednesday night.

Diamondbacks vs. Rockies Odds, Run Line and Total

Odds via DraftKings Sportsbook

Run Line

Diamondbacks -1.5 (-105)
Rockies +1.5 (-114)

Moneyline

Diamondbacks: -162
Rockies: +134

Total

11 (Over -111/Under -108)

Diamondbacks vs. Rockies Probable Pitchers

Arizona: Merrill Kelly (9-14, 5.00 ERA)
Colorado: Mason Adams (0-1, 5.09 ERA)

Diamondbacks vs. Rockies How to Watch

Date: Wednesday, Sept. 23
Time: 8:40 p.m. EST
Venue: Coors Field
How to Watch (TV): Rockies.TV/DBACKS.TV
Diamondbacks record: 83-74
Rockies record: 57-100

Diamondbacks vs. Rockies Best MLB Prop Bets

Rockies Best MLB Prop Bet

Hunter Goodman to Hit a Home Run (+287)

Earlier today, I shared in SI Betting’s best home run picks column – Daily Dinger – why Goodman is worth a look against Arizona:

Colorado Rockies catcher Hunter Goodman has 39 home runs in the 2026 season, posting an .834 OPS in the process.

An All-Star in 2026, Goodman has been one of the lone bright spots for a Rockies team that remains in the bottom of the standings in the NL West.

On Wednesday, he takes on the Arizona Diamondbacks and Merrill Kelly, who has given up 28 home runs in as many outings this season, posting a 5.00 ERA.

The D-Backs are barely alive in the NL wild card race, but I expect them to have a bit of a quick hook with Kelly if he struggles early on Wednesday. Still, Goodman is worth a look in this market, especially since he’s already homered off of Kelly in his career (15 at-bats).

The Rockies catcher has been slumping a bit as of late, homering just twice over his last 21 games and hitting .200 over that stretch. Still, he has 28 homers against right-handed pitching and hasn’t hit for a crazy average all season long.

Diamondbacks vs. Rockies Prediction and Pick

I don’t love either starting pitcher in this matchup, but the Rockies’ offense – dead last in Weighted Runs Created Plus – has struggled for most of 2026.

Kelly has allowed three or fewer earned runs in each of his last five starts, while Adams has a 5.09 ERA and a 5.84 expected ERA in his five MLB outings. There may not be a major advantage on the mound for the D-Backs, but they are clearly the better team this season.

Ultimately, this comes down to a massive motivation factor for Arizona. The D-Backs need every win they can get – and some help – to get into the playoffs.

Meanwhile, the Rockies have already lost 100 games and are poised to finish with the worst record in MLB.

Colorado lost by five runs in Game 1 of this series, and the D-Backs are 7-4 against them this season with five wins by two or more runs.

Pick: Diamondbacks Moneyline (-162 at DraftKings)

Odds refresh periodically and are subject to change.

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