Astros vs. Diamondbacks Prediction, Odds, Probable Pitchers and Prop Bets for Wednesday, July 23

The Astros are underdogs in their series finale on July 23.

Houston Astros outfielder Jose Altuve is a solid prop target on July 23. / Rick Scuteri-Imagn Images

The Houston Astros are one win away from a sweep of the Arizona Diamondbacks, but they’re set as underdogs on the road in the series finale on Wednesday.

Brandon Walter (3.66 ERA) is on the mound for the Astros, and he’s led the team to just a 2-6 record in his eight appearances in the 2025 season. 

Luckily for Houston, Walter will go up against the struggling Brandon Pfaadt (4.82 ERA), who ranks in the second percentile in expected ERA and first percentile in expected batting average against this season.

Arizona has somehow won 11 of Pfaadt’s 20 starts, but can it keep that going on Wednesday?

Let’s dive into the odds, my favorite prop bet and a prediction for this interleague matchup. 

Astros vs. Diamondbacks Odds, Run Line and Total

Odds via DraftKings Sportsbook

Run Line

• Astros +1.5 (-200)
• Diamondbacks -1.5 (+162)

Moneyline

• Astros: +104
• Diamondbacks: -126

Total

• 8.5 (Over -108/Under -113)

Astros vs. Diamondbacks Probable Pitchers

• Houston: Brandon Walter (1-3, 3.66 ERA)
• Arizona: Brandon Pfaadt (10-6, 4.82 ERA)

Astros vs. Diamondbacks How to Watch

• Date: Wednesday, July 23
• Time: 3:40 p.m. EST
• Venue: Chase Field
• How to Watch (TV): MLB Network, ARID, SCHN
• Astros record: 59-42
• Diamondbacks record: 50-52

Astros vs. Diamondbacks Best MLB Prop Bets

Astros Best MLB Prop Bet

• Jose Altuve to Hit a Home Run (+650)

Earlier today, I shared in SI Betting’s best home run picks – Daily Dinger – why Jose Altuve is a great target on Wednesday:

Houston Astros star Jose Altuve has quietly hit 17 home runs in the 2025 season, and he has a pretty favorable matchup on Tuesday afternoon against the Arizona Diamondbacks.

Arizona has righty Brandon Pfaadt on the mound, and he has posted an expected ERA of 6.22 this season, ranking in the second percentile in MLB. Overall, Pfaadt has given up 17 home runs in 20 starts, making him an easy player to fade in this market.

Altuve, on the other hand, has dominated against right-handed pitching this season, hitting .291 with 14 of his 17 home runs. The former league MVP has been on a tear as of late, hitting .329 with five homers over the last 28 days (22 games).

He’s certainly worth a look at +650 on Wednesday night. 

Astros vs. Diamondbacks Prediction and Pick

Houston has struggled in Walter’s outings this season, but the lefty has six appearances where he’s given up two or fewer earned runs. I think that gives Houston a pretty solid floor on Wednesday, especially since Pfaadt has not pitched well at all in 2025.

On the surface, some of Pfaadt’s numbers are decent.

He has a 10-6 win/loss record, a 4.35 Fielding Independent Pitching and a 1.26 WHIP. Not great, but not terrible.

However, the advanced numbers for Pfaadt, per Statcast, tell a much different story. He ranks right at the bottom of the league in several important categories: 

• Expected ERA: 6.22 (2nd percentile)
• Expected BAA: .306 (1st percentile)
• Average Exit Velocity Against: 92.0 (2nd percentile)
• Strikeout Percentage: 19.7% (34th percentile)
• Barrel Percentage: 13.2% (3rd percentile)
• Hard-Hit Percentage: 49.2% (4th percentile)

Teams are teeing off on Pfaadt, and the only reason his win/loss record is respectable is because Arizona has one of the better offenses in MLB.

I can’t back him as a favorite on Wednesday, even though he’s pitched better this month, lowering his actual ERA from 5.38 to 4.82. 

Pick: Astros Moneyline (+104 at DraftKings)

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Odds refresh periodically and are subject to change.

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