Diamondbacks vs Astros Prediction, Odds, Moneyline, Spread & Over/Under for July 21

Odds updated as of 10:12 a.m.

The Arizona Diamondbacks versus the Houston Astros is on the MLB schedule for Monday.

All the information you need to make smart wagers on this game at FanDuel Sportsbook can be found below. Check out all of the latest MLB betting lines here.

Diamondbacks vs Astros Game Info

• Arizona Diamondbacks (50-50) vs. Houston Astros (57-42)
• Date: Monday, July 21, 2025
• Time: 9:40 p.m. ET
• Venue: Chase Field -- Phoenix, Arizona
• Coverage: ARID and SCHN

Diamondbacks vs Astros Odds & Moneyline

• All MLB odds, betting lines and prop bets are available on FanDuel Sportsbook.
• Moneyline: ARI: (-142) | HOU: (+120)
• Spread: ARI: -1.5 (+146) | HOU: +1.5 (-176)
• Total: 8.5 -- Over: (-128) | Under: (+104)

Diamondbacks vs Astros Probable Starting Pitchers

Probable Pitchers: Zac Gallen (Diamondbacks) - 7-10, 5.40 ERA vs Colton Gordon (Astros) - 3-2, 4.67 ERA

The Diamondbacks will give the ball to Zac Gallen (7-10, 5.40 ERA), who is eyeing win No. 8 on the season, and the Astros will turn to Colton Gordon (3-2, 4.67 ERA). Gallen and his team have a record of 8-12-0 against the spread when he starts. Gallen's team is 5-7 this season when he starts and they are the moneyline favorite. The Astros have a 5-5-0 ATS record in Gordon's 10 starts with a set spread. The Astros have played while the underdog on the moneyline for four of Gordon's starts this season, and they won every time.

Diamondbacks vs Astros Prediction & Pick

All MLB win probability predictions and picks are according to numberFire.
Prediction: Diamondbacks win (50.7%)

Diamondbacks vs Astros Moneyline

• Arizona is the favorite, -142 on the moneyline, while Houston is a +120 underdog on the road.

Diamondbacks vs Astros Spread

• The Astros are at +1.5 on the runline against the Diamondbacks. The Astros are -176 to cover the spread, and the Diamondbacks are +146.

Diamondbacks vs Astros Over/Under

• A total of 8.5 runs has been set for the Diamondbacks-Astros game on July 21, with the over available at -128 and the under at +104.

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Diamondbacks vs Astros Betting Trends

• The Diamondbacks have won in 32, or 50.8%, of the 63 contests they have been named as odds-on favorites in this year.
• This season Arizona has come away with a win 17 times in 31 chances when named as a favorite of at least -142 on the moneyline.
• The Diamondbacks and their opponents have gone over in 52 of their 97 games with a total set by sportsbooks this season.
• The Diamondbacks are 47-50-0 against the spread in their 97 games with a line set by sportsbooks this season.
• The Astros have won 60% of the games this season they were the underdog on the moneyline (18-12).
• Houston is 7-1 (winning 87.5% of its games) when it has played as a moneyline underdog of +120 or longer.
• The Astros have combined with opponents to hit the over on the total 42 times this season for a 42-54-2 record against the over/under.
• The Astros have a 50-48-0 record ATS this season (covering 51% of the time).

Diamondbacks Player Leaders

• Geraldo Perdomo has an OPS of .793, fueled by an OBP of .373 to go with a slugging percentage of .420. He has a .272 batting average, as well.
• Among all qualified hitters in baseball, he ranks 54th in batting average, 17th in on-base percentage, and 85th in slugging.
• Perdomo will look for his fourth straight game with a hit in this matchup. During his last five outings he is hitting .333 with a triple, three walks and seven RBIs.
• Eugenio Suarez has 92 hits, which is best among Arizona batters this season. He's batting .257 with 53 extra-base hits. He's also slugging .601 with an on-base percentage of .328.
• Among qualifying batters, his batting average ranks him 84th, his on-base percentage 77th, and his slugging percentage fourth.
• Suarez takes a five-game streak with at least one hit into this one. During his last five outings he is batting .500 with a double, six home runs, four walks and 10 RBIs.
• Josh Naylor is batting .292 with a .452 slugging percentage and 58 RBI this year.
• Corbin Carroll is batting .251 with a .328 OBP and 48 RBI for Arizona this season.
• Carroll heads into this game on a two-game hitting streak. During his last five outings he is hitting .261 with two doubles, three triples, a walk and an RBI.

Astros Player Leaders

• Jose Altuve has accumulated a team-high .465 slugging percentage. He's batting .278 with an on-base percentage of .338.
• Including all the qualifying hitters in the majors, his batting average ranks 43rd, his on-base percentage is 62nd, and he is 47th in slugging.
• Yainer Diaz has 11 doubles, a triple, 13 home runs and 14 walks while batting .239. He's slugging .394 with an on-base percentage of .271.
• Including all qualifying hitters, he ranks 121st in batting average, 154th in on-base percentage and 110th in slugging percentage.
• Cam Smith has 17 doubles, two triples, seven home runs and 27 walks while hitting .270.
• Christian Walker is batting .227 with 12 doubles, a triple, 13 home runs and 25 walks.

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