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

Odds updated as of 1:12 p.m.

MLB action on Monday includes the Arizona Diamondbacks taking on the Houston Astros.

All the info you need to make smart bets 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 (+142) | HOU: +1.5 (-172)
• Total: 9 -- Over: (-104) | Under: (-118)

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

This contest's pitching matchup is set, as the Diamondbacks will send Zac Gallen (7-10) to the mound, while Colton Gordon (3-2) will answer the bell for the Astros. Gallen and his team are 8-12-0 ATS this season when he starts. Gallen's team has a record of 5-7 this season when he starts and they are the favorite on the moneyline. The Astros have gone 5-5-0 ATS in Gordon's 10 starts with a set spread. The Astros won each of Gordon's four starts this season that they were the moneyline underdog.

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

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

Diamondbacks vs Astros Spread

• The Diamondbacks are hosting the Astros and are favored by 1.5 runs (+142 to cover) on the runline. Houston is -172 to cover.

Diamondbacks vs Astros Over/Under

• Diamondbacks versus Astros on July 21 has an over/under of 9 runs, with the odds on the over -104 and the under set at -118.

Bet on Arizona Diamondbacks vs. Houston Astros on FanDuel today!

Diamondbacks vs Astros Betting Trends

• The Diamondbacks have been chosen as favorites in 63 games this year and have walked away with the win 32 times (50.8%) in those games.
• This year Arizona has won 17 of 31 games when listed as at least -142 on the moneyline.
• The Diamondbacks' games have gone over the total in 52 of their 97 opportunities.
• The Diamondbacks have posted a record of 47-50-0 against the spread this season.
• The Astros have gone 18-12 in games they were listed as the moneyline underdog (winning 60% of those games).
• When playing as a moneyline underdog with odds of +120 or longer, Houston has a record of 7-1 (87.5%).
• The Astros have played in 98 games with a set over/under, and have combined with opponents to go over the total 42 times (42-54-2).
• The Astros have a 50-48-0 record against the spread this season.

Diamondbacks Player Leaders

• Geraldo Perdomo leads Arizona OPS (.793) this season. He has a .272 batting average, an on-base percentage of .373, and a slugging percentage of .420.
• Among all qualifying batters in MLB, 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 leads Arizona in total hits (92) this season while batting .257 with 53 extra-base hits. He's slugging .601 with an on-base percentage of .328.
• Among qualified hitters, he ranks 84th in batting average, 77th in on-base percentage and fourth in slugging percentage.
• Suarez has picked up at least one hit in five straight games. During his last five outings he is batting .500 with a double, six home runs, four walks and 10 RBIs.
• Josh Naylor has collected 98 base hits, an OBP of .361 and a slugging percentage of .452 this season.
• Corbin Carroll has 21 home runs, 48 RBI and a batting average of .251 this season.
• Carroll brings a two-game hitting streak into this game. In his last five games he is batting .261 with two doubles, three triples, a walk and an RBI.

Astros Player Leaders

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

Sign up for FanDuel Sportsbook and FanDuel Daily Fantasy today!