Diamondbacks vs. Pirates Prediction, Odds, Probable Pitchers, Prop Bets for Monday, July 27

The Arizona Diamondbacks have a one-game lead on the Pittsburgh Pirates in the National League wild card race heading into Monday’s series opener in Pittsburgh.

Both of these teams have a real case to make the playoffs, as Pittsburgh has one of the best offenses in MLB while the D-Backs are three games over .500 this month and have just a minus-3 run differential in 2026.

On Monday, Arizona has right-hander Merril Kelly (5.12 ERA) on the mound, as he looks to build on a strong month of July. Kelly has some awful season-long numbers, but he has a 2.45 ERA in four starts this month, leading Arizona to a 3-1 record. Still, his Fielding Independent Pitching is pushing 5.00 during that four-start stretch.

Kelly will take on Pittsburgh right-hander Mitch Keller (4.90 ERA), who has allowed eight runs across three starts this month.

Oddsmakers have Pittsburgh favored at home, as the D-Backs are a worse team on the road (five games under .500) than they are at home (nine games over .500).

Here’s a look at the odds, a player prop to bet and my prediction for Monday’s series opener.

Diamondbacks vs. Pirates Odds, Run Line and Total

Odds via DraftKings Sportsbook

Run Line

Diamondbacks +1.5 (-199)
Pirates -1.5 (+163)

Moneyline

Diamondbacks: +101
Pirates: -121

Total

9 (Over -105/Under -114)

Diamondbacks vs. Pirates Probable Pitchers

Arizona: Merrill Kelly (8-8, 5.12 ERA)
Pittsburgh: Mitch Keller (6-7, 4.90 ERA)

Diamondbacks vs. Pirates How to Watch

Date: Monday, July 27
Time: 6:40 p.m. EST
Venue: PNC Park
How to Watch (TV): MLB.TV/DBACKS.TV
Diamondbacks record: 55-51
Pirates record: 54-52

Diamondbacks vs. Pirates Best MLB Prop Bets

Pirates Best MLB Prop Bet

Esmerlyn Valdez to Hit a Home Run (+405)

Earlier today, I shared in SI Betting’s best home run picks column – Daily Dinger – why Valdez is undervalued against Arizona:

Pittsburgh Pirates rookie Esmerlyn Valdez has put together a strong 2026 season after making his debut in late May. He’s hit 14 home runs in 37 games (33 starts), and he’s posted a .293 batting average and 1.092 OPS in the process.

Pittsburgh has one of the best offenses in MLB, and Valdez has become an extremely important bat in the lineup, hitting cleanup during this recent hot stretch. The rookie is hitting .309 with nine homers over the last 28 days (22 games), and he’s homered seven times against both right-handed and left-handed pitching.

That makes him pretty matchup proof, and I love this prop for him (at +405) against Arizona Diamondbacks righty Merrill Kelly.

The veteran right-hander has struggled in 2026, posting a 5.12 ERA while allowing 22 home runs in 18 outings. I think Valdez is undervalued in this matchup especially since Kelly has allowed at least one homer in five straight outings.

Diamondbacks vs. Pirates Prediction and Pick

Both of these starters have struggled mightily in the 2026 season, which could lead to a high-scoring affair on Monday.

Kelly ranks in the first percentile in expected ERA and expected batting average against, even though he’s allowed three or fewer runs in each of his starts this month. Kelly still has a 7.25 expected ERA, and now he’s taking on an elite Pittsburgh offense.

The Pirates are third in the league in OPS, second in runs scored and fourth in Weighted Runs Created Plus (wRC+). The D-Backs are also in the top half of the league in runs scored, despite ranking in the bottom 10 in wRC+.

Keller (4.90 ERA) ranks in just the 13th percentile in expected ERA and the fifth percentile in expected BAA, and he has a 5.85 ERA since June 1.

The right-hander has given up at least three runs in 10 of his last 12 appearances.

Pittsburgh has hit the OVER in 59.2 percent of its games this season – the best mark in MLB – so I’d expect a high-scoring series opener on July 27.

Pick: OVER 9 (-105 at DraftKings)

Odds refresh periodically and are subject to change.

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