Diamondbacks vs. Giants Prediction, Odds, Probable Pitchers and Prop Bets for Tuesday, May 13

Betting odds, pick and prediction for the Arizona Diamondbacks-San Francisco Giants matchup on May 13.

Arizona Diamondbacks pitcher Brandon Pfaadt is a solid prop target on Tuesday. / Matt Kartozian-Imagn Images

The Arizona Diamondbacks pulled out a 2-1 win against the San Francisco Giants on Monday night, and they’ll look to gain more ground in the NL West standings as road favorites on Tuesday night.

Brandon Pfaadt (6-2, 3.28 ERA) gets the ball for Arizona fresh off a scoreless outing in a win over the Los Angeles Dodgers. The young righty has been one of the D-Backs’ more trusted arms, and he’s shockingly earned the decision in every one of his starts this season.

San Francisco will counter with a former Cy Young award winner – lefty Robbie Ray – who has led the Giants to a perfect 8-0 record in his starts.

So, which NL West team has the advantage on Tuesday night?

Let’s take a look at the odds, players to watch in the prop market, and my prediction for this NL West battle. 

Diamondbacks vs. Giants Odds, Run Line and Total

Odds via DraftKings Sportsbook.

Run Line

• Diamondbacks -1.5 (+154)
• Giants +1.5 (-185)

Moneyline

• Diamondbacks: -115
• Giants: -105

Total

• 7.5 (Over -110/Under -110)

Diamondbacks vs. Giants Probable Pitchers

• Arizona: Brandon Pfaadt (6-2, 3.28 ERA)
• San Francisco: Robbie Ray (5-0, 2.84 ERA)

Diamondbacks vs. Giants How to Watch

• Date: Tuesday, May 13
• Time: 9:45 p.m. EST
• Venue: Oracle Park
• How to Watch (TV): MLB Network, NBCS-BA, ARID
• Diamondbacks record: 22-20
• Giants record: 24-18

Diamondbacks vs. Giants Best MLB Prop Bets

Diamondbacks Best MLB Prop Bet

• Brandon Pfaadt OVER 4.5 Strikeouts (-165)

I love this prop for Pfaadt on Tuesday, as he’s punched out five or more batters in six of his eight starts this season, including each of his last five outings.

The Giants are very prone to the punchout this season, ranking 22nd in MLB in K’s per game (8.64). Not only that, but the Giants are averaging 9.67 strikeouts per game over their last three matchups. 

Pfaadt ranks in just the 44th percentile in strikeout percentage this season, but he does a great job at getting hitters to chase pitches (86th percentile in chase rate). Since he’s worked into the sixth inning in all but one of his outings this season, I think Pfaadt is a steal at this number on Tuesday.  

Diamondbacks vs. Giants Prediction and Pick

Earlier today, I shared in SI Betting’s MLB Best Bets column – Walk-Off Wagers – a way to back both starters in Tuesday’s contest: 

The Diamondbacks have one of the best offenses in Major League Baseball this season, ranking fourth in OPS, but I think Tuesday’s matchup between these divisional foes will be a low-scoring one.

Both starters in this game – San Francisco’s Robbie Ray and Arizona’s Brandon Pfaadt – have gotten off to strong starts in 2025, so I’m looking to the UNDER in the first five innings for my best bet.

This season, Ray has a 2.84 ERA, and he only has one start where he’s given up more than three earned runs. In fact, the former Cy Young award winner has led the Giants to a perfect 8-0 record in his starts, and he’s put together an impressive 1.19 WHIP to go along with his ERA. 

On the Arizona side of things, Pfaadt is coming off 6.1 innings of scoreless ball in a win over the Los Angeles Dodgers, lowering his ERA to 3.28 in the process. He also has done a solid job of limiting baserunners, posting a 1.22 WHIP, and he’s allowed three or fewer earned runs in six of his eight starts in 2025.

While Pfaadt and Ray are both going to need to have strong games to keep this total below 4.5 in the first five frames, Ray has put together four straight outings with two or fewer earned runs allowed. 

Since the Arizona bullpen has a 4.95 ERA this season, I prefer this play on the total much more than a full-game UNDER on Tuesday night. 

Pick: First Five Innings UNDER 4.5 (-145 at DraftKings)

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Odds refresh periodically and are subject to change.

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