In what started out as a four-team race for control of the NL West, the Arizona Diamondbacks are in danger of falling farther behind the pace. At the halfway point of the season, Arizona trails the Los Angeles Dodgers by nine games, sitting at 41-39. The Diamondbacks have, however, picked up four of their last six games against the league’s two worst teams, the Colorado Rockies and the Chicago White Sox.
Arizona has a chance to continue its rally against a Miami Marlins unit that, while not quite on the same level as Colorado and Chicago, isn’t great either. The Marlins are 34-45, 12.5 games behind the New York Mets for first place in the NL East.
Tonight, the Diamondbacks will start veteran Merrill Kelly, while Miami will counter with young flamethrower Eury Pérez.
Let’s break down this matchup with some odds and lines at DraftKings Sportsbook.
Miami Marlins at Arizona Diamondbacks prediction, preview
Kelly has turned in one of his most impressive seasons at the age of 36, pitching 93.0 innings, amassing a 7-3 record, and posting a solid 3.39 ERA. In fact, since a blow-up outing in his second start of the season against the New York Yankees, in which he gave up nine runs in 3.2 innings, he has pitched to a 2.68 ERA and, more encouragingly, a 2.69 FIP figure. He’s also forced 10 or more whiffs in each of his last nine starts. Statcast figures suggest that he’s been slightly lucky — he’s given up just an 18th-percentile hard-hit percentage and a 22nd-percentile average exit velocity, so his expected ERA is somewhat worse than his actual mark — but either way, I trust him to give his team a chance.
Pérez hasn’t been so good this season, but to be fair, it’s been three starts. The Dominican hasn’t yet finished the fifth inning, giving up eight runs in 11.2 innings, but interestingly enough, his FIP figure is 2.99, indicating that he’s been exceptionally unlucky. He also has a strong track record of success; in his rookie season in 2023, he threw 91.1 innings and posted a 3.15 ERA, finishing seventh in NL Rookie of the Year voting before undergoing Tommy John surgery and missing the entire 2024 season and the first few months of 2025. His velocity and spin rates have actually gone up slightly since his rookie season, so it doesn’t seem like his elbow injury is affecting him too much, even if he’s struggled with his control.
Neither team has a great bullpen; Arizona’s relievers have recorded the league’s third-highest ERA and the Marlins’ bullpen has been the league’s eighth-worst, so it might be reasonable to expect a high-scoring game. Both teams have had above-average offenses in June, as the Diamondbacks have posted the league’s third-best OPS so far this month and Miami is tied for 15th. However, Arizona will have to learn how to operate without Corbin Carroll, who ended up on the injured list with a fractured wrist after getting hit by a pitch on June 18. The Diamondbacks’ revitalized offense is running through Eugenio Suárez, who’s slashing .381/.438/.929 over his last 12 games.
Miami Marlins at Arizona Diamondbacks pick, best bet
Best Bet: Eury Pérez Race to 3 Strikeouts (+155)
The underlying figures indicate that Pérez isn’t fundamentally a different pitcher than he was in 2023, and with the small sample size, he could easily work his way back towards the mean. That season, he had a 28.9% strikeout rate, higher than Kelly’s 25.0% this season.
Strong Lean: Xavier Edwards O0.5 Stolen Bases (+210)
As a big fan of the Ducks on the Pod’s barrel watch, I know that Edwards is one of three qualified batters this season not to record a barrel. I also know that thanks to his 57th-percentile expected batting average, a 75th-percentile walk percentage, and 67th-percentile sprint speed, he’s always a threat to steal a base. Kelly has been above-average at preventing runners from taking extra bases this season, but he was poor in that stat in each of the prior three seasons.
