Arizona Diamondbacks vs San Francisco Giants Prediction, Odds and Picks for Today, 05/25/26

I don’t like backing the San Francisco Giants very much this season as their offense can be anemic and their performance to this point has been underwhelming. That being said, I do favor them at current pricing as they host the Diamondbacks on Memorial Day. Landen Roupp has been the Giants best pitcher in 2026, posting a 3.27 ERA through his first 55 innings of work. His 2.82 xERA and 2.59 FIP are even stronger marks and give me confidence he can perform well today. Roupp ranks 94th percentile or better in ground ball rate, hard-hit rate, and as a result, barrel rate. He also earns a healthy 27.2% strikeout rate. That is a profile I like to bet on. Roupp tossed 6 innings of 1-run ball with 0 walks against Arizona last start and now faces them in his pitcher-friendly home environment.

Merrill Kelly is set to start for Arizona, marking his 2nd consecutive start against this Giants lineup. Like Roupp, Kelly is tasked with a close proximity rematch which is not my favorite spot to back. Unlike Roupp, Kelly does not have strong underlying metrics this season. He enters Monday with a 5.71 ERA and an 8.17 xERA. Kelly is 1st percentile in barrel rate while earning a K-BB% of just 5%. The Giants are not a good lineup, but they did get 8 hits and 3 runs off Merrill the first time around. I favor San Francisco in this game.

Arizona Diamondbacks vs San Francisco Giants prediction: Giants ML (-135) available at time of publishing. Playable to -140.

Sign up for Polymarket RIGHT NOW to get instant access and a $50 trading bonus after you make your first $20 deposit! You can join Polymarket by clicking here and trade on our Diamondbacks vs Giants predictions.