Diamondbacks vs. Rockies Prediction, Odds, Probable Pitchers and Prop Bets for Saturday, June 21

Betting odds, pick and prediction for the Arizona Diamondbacks-Colorado Rockies matchup on Saturday.

Arizona Diamondbacks slugger Lourdes Gurriel Jr. is a solid prop target on Saturday. / Joe Rondone/The Republic / USA TODAY NETWORK via Imagn Images

The Arizona Diamondbacks hung 14 runs on the Colorado Rockies on Friday night, and they’re looking to pick up another win on Saturday with righty Merrill Kelly on the mound.

Kelly (6-3, 3.41 ERA) has been solid for Arizona this season, posting 10 starts this season with two or fewer earned runs allowed. He opened the month of June with 13.0 scoreless innings, but he did give up four runs in his last outing.

The D-Backs still are heavily favored to win on Saturday, as Carson Palmquist (7.76 ERA) is on the mound for Colorado. The Rockies are just 1-5 in Palmquist’s six starts and they have just 17 wins all season.

After the D-Backs teed off on lefty Austin Gomber on Friday, they’ll look to do the same against another young lefty on Saturday.

Here’s a breakdown of the odds, my favorite prop bet and more for Saturday’s NL West showdown. 

Diamondbacks vs. Rockies Odds, Run Line and Total

Odds via DraftKings Sportsbook.

Run Line

• Diamondbacks -1.5 (-145)
• Rockies +1.5 (+119)

Moneyline

• Diamondbacks: -220
• Rockies: +178

Total

• 12 (Over -113/Under -107)

Diamondbacks vs. Rockies Probable Pitchers

• Arizona: Merrill Kelly (6-3, 3.41 ERA)
• Colorado: Carson Palmquist (0-4, 7.76 ERA)

Diamondbacks vs. Rockies How to Watch

• Date: Saturday, June 21
• Time: 9:10 p.m. EST
• Venue: Coors Field
• How to Watch (TV): COLR, ARID
• Diamondbacks record: 38-37
• Rockies record: 17-59

Diamondbacks vs. Rockies Best MLB Prop Bets

Diamondbacks Best MLB Prop Bet

• Lourdes Gurriel Jr. to Hit a Home Run (+360)

Earlier today, I shared in SI Betting’s best home run picks – Daily Dinger – why Gurriel is a steal at this price: 

Whenever the Arizona Diamondbacks are facing the Colorado Rockies, I’m looking to target a player to go deep – like I did with Ketel Marte on Friday.

On Saturday, I’m targeting Lourdes Gurriel Jr., who has been elite against left-handed pitching in the 2025 season, hitting .303 with a trio of home runs. On Saturday, Gurriel will take on Rockies lefty Carson Palmquist, who has a 7.76 ERA this season and has given up seven homers in six appearances.

The total for this game is all the way up at 12.5, so oddsmakers are expecting some fireworks on offense.

Gurriel has been great over the last 28 days, hitting .330, and he should tee off on this weak Rockies pitching staff. Following Palmquist, the Rockies will turn to a bullpen that has a 4.71 ERA and has given up 40 homers in the 2025 season. 

Diamondbacks vs. Rockies Prediction and Pick

The Rockies are the worst team on the run line in the 2025 season, going 30-46, and it’s nearly impossible to trust them with Palmquist on the mound.

The lefty has pitched five innings just once in six starts, allowing more hits than innings pitched. Colorado already has the worst team ERA in MLB (5.59), and Palmquist is a major contributor to that in his starts with a 7.76 ERA.

Kelly, on the other hand, has been pretty consistent in the 2025 season, allowing two or fewer earned runs in 10 of his 15 outings. He does have an expected ERA of just 3.99 in 2025, but that should be good enough to beat this Colorado team.

The D-Backs also thrive against left-handed pitching, ranking 10th in MLB in OPS and 11th in batting average against southpaws this season. 

Pick: Diamondbacks -1.5 (-145 at DraftKings)

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Odds refresh periodically and are subject to change.

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