Colorado Rockies vs. Arizona Diamondbacks prediction, pick for Wednesday 8/12/26

NL West foes will meet for a rubber match this afternoon in Phoenix. The Diamondbacks (64-57), on track for a playoff berth, got upset last night at home. It was the last-place Rockies (47-73) that came away with a 3-2 victory. If Arizona is going to bounce back, it’ll likely be due to starting pitcher Merrill Kelly. Can he lead the Snakes to a series victory on Wednesday?

The D-backs are favorites (-165) over the Rockies; the over/under is set at nine runs. Below, I’ve laid out my preview, prediction, and best bet for Wednesday’s showdown between Colorado and Arizona on DraftKings Sportsbook.

Rockies vs. Diamondbacks pick, best bet today

Diamondbacks -1.5 (+119): Kelly isn’t great, but he comes into this one with momentum and a track record of success vs. Colorado. As for Feltner, his propensity for giving up homers doesn’t inspire confidence against a deep D-backs lineup.

Rockies vs. Diamondbacks prediction, preview

Ryan Feltner will get the nod this afternoon for the visitors. Colorado’s pitching staff is arguably the worst in baseball. As a result, any pitcher with a 5.71 ERA and 1.45 WHIP are among the team’s better starters. That’s the reality for Feltner, a sixth-year pro that has shown flashes but lacks consistency. Toeing the slab for half of his games at Coors Field doesn’t help, but it’s not the only explanation for such mediocre numbers. In fact, the right-hander has been slightly less effective when pitching on the road (5.85 ERA). He’s within the 11th percentile or worse in xERA (5.46), chase rate (26.3%), strikeout rate (16.5%) and barrel rate (11.3%).

Taking the mound has been a struggle for Feltner against almost everyone this season. Now, he’ll have to do so against one of baseball’s hottest lineups. The Diamondbacks have scored 185 runs since July 1st, tied for sixth-most in the majors during that time. What’s remarkable is that this group hasn’t been carried by superstars. Corbin Carroll (118 wRC+) and Ketel Marte (104 wRC+) are both great players, but neither has been at their absolute best in 2026. However, seven different Arizona hitters (min. 100 plate appearances) have a wRC+ above 100.

It’s not as if Kelly has been dominant on the mound himself. Arizona’s hurler is in the midst of a bizarre campaign. Per Savant, he ranks as one of the league’s worst starters. A 6.97 xERA and .300 xBA are both in the bottom percentile among qualified pitchers. With that being said, Kelly’s standard numbers are far more respectable (4.88 ERA, 1.47 WHIP). The 37-year-old has allowed two earned runs or less in six of his previous seven appearances. During his lone meeting with the Rockies, back on May 15th, the right-hander tossed a nine-inning, one-run gem at Coors Field.

Even casual MLB fans are aware that Rockies hitters get inflated numbers at home. That’s the case once again in 2026; they’re averaging the 11th-fewest runs per game on the road (4.34). There are some big bats in this lineup, headlined by Hunter Goodman and his 34 homers. Colorado has recorded the tenth-worst OPS against right-handed pitching during away games (.694). As previously mentioned, Kelly had little issue silencing this group in Denver. That spells trouble for the visitors this afternoon.

Best Bet: Diamondbacks ML (+119)

Feltner is no ace, posting an ERA of nearly 6.00. As for Kelly, his poor peripherals might be a bit overblown. After all, the former All-Star has been terrific since the start of July. Arizona’s lineup has rounded into form, looking like one of the league’s best in recent weeks. That’s almost impossible to ignore at home against a subpar arm.

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