Pirates vs. Diamondbacks Prediction, Odds, Probable Pitchers and Prop Bets for Wednesday, May 28

The D-Backs are favored at home in this series finale.

The Pirates are underdogs with Paul Skenes on the mound. / Charles LeClaire-Imagn Images

The Pittsburgh Pirates and Arizona Diamondbacks face off in the rubber match of their three-game series on Wednesday, May 28.

This matchup features two star pitchers in Pittsburgh’s Paul Skenes – the favorite to win the NL Cy Young this season – and Arizona’s Zac Gallen.

Gallen is off to a slow start in the 2025 season, posting a 5.25 ERA, but the D-Backs are still favored at home in the odds for this series finale.

Can Skenes put together a shutdown performance to lead the Pirates to a win in the series finale?

Here’s a breakdown of the odds, players to watch in the prop market, and my game prediction for Wednesday’s NL showdown. 

Pirates vs. Diamondbacks Odds, Run Line and Total

Odds via DraftKings Sportsbook.

Run Line

• Pirates +1.5 (-205)
• Diamondbacks -1.5 (+170)

Moneyline

• Pirates: +102
• Diamondbacks: -122

Total

• 7.5 (Over -115/Under -105)

Pirates vs. Diamondbacks Probable Pitchers

• Pittsburgh: Paul Skenes (3-5, 2.36 ERA)
• Arizona: Zac Gallen (3-6, 5.25 ERA)

Pirates vs. Diamondbacks How to Watch

• Date: Wednesday, May 28
• Time: 3:40 p.m. EST
• Venue: Chase Field
• How to Watch (TV): ARID, SportsNet PT
• Pirates record: 20-36
• Diamondbacks record: 27-28 

Pirates vs. Diamondbacks Best MLB Prop Bets

Diamondbacks Best MLB Prop Bet

• Zac Gallen OVER 2.5 Walks Allowed (+145)

This season, Zac Gallen has struggled with his control, walking 29 batters in 61.2 innings. 

He ranks in just the 24th percentile in MLB in walk percentage, and he’s given up three or more walks in six of his 11 starts.

While the Pirates' offense is not good, it does rank eighth in MLB in walks drawn in the 2025 season. So, I wouldn’t be shocked to see Gallen (1.36 WHIP) walk three or more batters again. This is worth a look at the current odds on Wednesday. 

Pirates vs. Diamondbacks Prediction and Pick

Earlier today, I shared in SI Betting’s MLB Best Bets column – Walk-Off Wagers – why the UNDER is the play with Skenes and Gallen on the mound: 

When Paul Skenes is on the mound, it’s hard not to bet on a Pittsburgh Pirates matchup.

The star pitcher has an insanely impressive 2.36 ERA this season despite the fact that the Pirates are just 4-7 in his starts. Skenes has given up two or fewer earned runs in nine of his outings, and he’s been lights out in the month of May, posting a 2.32 ERA across 31.0 innings of work.

On Wednesday, I’m eyeing the UNDER in the Pirates-Arizona Diamondbacks matchup, as Pittsburgh's offense has not given Skenes support all season long.

Not only do the Pirates rank dead last in MLB in runs scored and 29th in OPS, but they have scored four or fewer runs in nine of the 11 starts Skenes has made in 2025. 

Things won’t be easy against Arizona’s Zac Gallen, who has been one of the better pitchers in baseball in recent seasons – despite a slow start in 2025. Gallen currently has a 5.25 ERA, but I think this is a prime bounce-back spot for the righty against one of the worst offenses in baseball.

I’ll trust Skenes to keep this Arizona offense in check, as six of his outings already in 2025 have combined for seven or fewer runs. 

Pick: UNDER 7.5 (-105 at DraftKings)

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Odds refresh periodically and are subject to change.

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