Diamondbacks vs Giants Prediction, Odds, Moneyline, Spread & Over/Under for May 20

Odds updated as of 3:12 p.m.

In MLB action on Wednesday, the Arizona Diamondbacks take on the San Francisco Giants.

All the information you need to make smart wagers on this game at FanDuel Sportsbook can be found below. Check out all of the latest MLB betting lines here.

Diamondbacks vs Giants Game Info

• Arizona Diamondbacks (24-23) vs. San Francisco Giants (20-29)
• Date: Wednesday, May 20, 2026
• Time: 3:40 p.m. ET
• Venue: Chase Field -- Phoenix, Arizona
• Coverage: Dbacks.TV and NBCS-BA

Diamondbacks vs Giants Odds & Moneyline

• All MLB odds, betting lines and prop bets are available on FanDuel Sportsbook.
• Moneyline: ARI: (-124) | SF: (+106)
• Spread: ARI: -1.5 (+160) | SF: +1.5 (-194)
• Total: 8.5 -- Over: (-110) | Under: (-110)

Diamondbacks vs Giants Probable Starting Pitchers

Probable Pitchers: Merrill Kelly (Diamondbacks) - 3-3, 5.91 ERA vs Tyler Mahle (Giants) - 1-5, 5.59 ERA

This contest's pitching matchup is set, as the Diamondbacks will send Merrill Kelly (3-3) to the mound, while Tyler Mahle (1-5) will take the ball for the Giants. Kelly's team is 3-3-0 against the spread in his starts this season. Kelly's team is 1-1 this season when he starts and they're favored on the moneyline. The Giants are 3-6-0 against the spread when Mahle starts. The Giants have a 2-5 record in Mahle's seven starts this season when they were the underdog on the moneyline.

Diamondbacks vs Giants Prediction & Pick

All MLB win probability predictions and picks are according to numberFire.
Prediction: Diamondbacks win (54.5%)

Diamondbacks vs Giants Moneyline

• The moneyline numbers for Diamondbacks vs. Giants reveal Arizona as the favorite (-124) and San Francisco as the underdog (+106) on the road.

Diamondbacks vs Giants Spread

• The Diamondbacks are hosting the Giants and are favored by 1.5 runs (+160 to cover) on the runline. San Francisco is -194 to cover.

Diamondbacks vs Giants Over/Under

• A total of 8.5 runs has been set for the Diamondbacks-Giants game on May 20, with the over available at -110 and the under at -110.

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Diamondbacks vs Giants Betting Trends

• The Diamondbacks have come away with 11 wins in the 17 contests they have been listed as the favorites in this season.
• This season Arizona has been victorious six times in nine chances when named as a favorite of at least -124 on the moneyline.
• The Diamondbacks and their opponents have gone over in 23 of their 46 games with a total set by sportsbooks this season.
• The Diamondbacks are 28-18-0 against the spread in their 46 games that had a posted line this season.
• The Giants have won 13 of the 35 games they were the underdog on the moneyline this season (37.1%).
• In games it has played as a moneyline underdog with odds of +106 or longer, San Francisco has gone 10-13 (43.5%).
• The Giants have combined with opponents to hit the over on the total 21 times this season for a 21-25-3 record against the over/under.
• The Giants have a 20-29-0 record ATS this season (covering 40.8% of the time).

Diamondbacks Player Leaders

• Ildemaro Vargas leads Arizona in slugging percentage (.543) thanks to 17 extra-base hits. He has a .340 batting average and an on-base percentage of .359.
• Among qualifying hitters in MLB, he is second in batting average, 47th in on-base percentage, and 13th in slugging.
• Vargas has hit safely in three straight games. During his last five outings he is batting .391 with a double and three RBIs.
• Corbin Carroll has 45 hits and an OBP of .395, both of which lead the Diamondbacks this season. He's batting .285 and slugging .563.
• Among qualifying hitters, his batting average places him 34th, his on-base percentage 11th, and his slugging percentage 10th.
• Carroll enters this game looking to extend his eight-game hit streak. During his last 10 outings he is hitting .353 with three doubles, two triples, two home runs, 10 walks and four RBIs.
• Nolan Arenado is batting .278 with a .477 slugging percentage and 25 RBI this year.
• Arenado enters this matchup with three games in a row with at least one hit. In his last five games he is batting .313 with three doubles, a home run, five walks and five RBIs.
• Geraldo Perdomo has two home runs, 12 RBI and a batting average of .222 this season.

Giants Player Leaders

• Luis Arraez has a .360 on-base percentage and a .425 slugging percentage, both team-high numbers for the Giants. He's batting .320.
• Including all qualifying hitters in the big leagues, he is seventh in batting average, 45th in on-base percentage and 66th in slugging percentage.
• Casey Schmitt paces his team with 45 hits. He has a batting average of .294 while slugging .516 with an on-base percentage of .339.
• Including all qualified hitters, his batting average places him 20th, his on-base percentage ranks 74th, and he is 20th in slugging.
• Jung Hoo Lee is batting .268 with 10 doubles, a triple, three home runs and 10 walks.
• Rafael Devers is hitting .246 with 11 doubles, six home runs and 13 walks.

Diamondbacks vs Giants Head to Head

• 5/19/2026: 5-3 ARI (Favorite: Diamondbacks, Spread: -1.5, Total: 8.5, Favorite Moneyline: -124, Underdog Moneyline: +106)
• 5/18/2026: 12-2 ARI (Favorite: Diamondbacks, Spread: -1.5, Total: 9, Favorite Moneyline: -136, Underdog Moneyline: +116)
• 9/17/2025: 5-1 SF (Favorite: Diamondbacks, Spread: -1.5, Total: 9, Favorite Moneyline: -108, Underdog Moneyline: -108)
• 9/16/2025: 6-5 ARI (Favorite: Diamondbacks, Spread: -1.5, Total: 9, Favorite Moneyline: -130, Underdog Moneyline: +110)
• 9/15/2025: 8-1 ARI (Favorite: Diamondbacks, Spread: -1.5, Total: 9, Favorite Moneyline: -132, Underdog Moneyline: +112)
• 9/10/2025: 5-3 ARI (Favorite: Giants, Spread: -1.5, Total: 8.5, Favorite Moneyline: -126, Underdog Moneyline: +108)
• 9/9/2025: 5-3 SF (Favorite: Giants, Spread: -1.5, Total: 7.5, Favorite Moneyline: -142, Underdog Moneyline: +120)
• 9/8/2025: 11-5 SF (Favorite: Giants, Spread: -1.5, Total: 7.5, Favorite Moneyline: -174, Underdog Moneyline: +146)
• 7/3/2025: 7-2 SF (Favorite: Giants, Spread: -1.5, Total: 8.5, Favorite Moneyline: -126, Underdog Moneyline: +108)
• 7/2/2025: 6-5 SF (Favorite: Diamondbacks, Spread: -1.5, Total: 8.5, Favorite Moneyline: -146, Underdog Moneyline: +124)

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