Patrick Sandoval Is a Perfect Fit for the Red Sox

The Red Sox aren’t ready to break for the holidays just yet. On Friday morning, Jeff Passan announced that Boston had signed left-handed starter Patrick Sandoval to a backloaded two-year, $18.25-million contract. Caleb Kohn has already broken down the nuts and bolts of the deal, so in this article we’ll dig a little deeper career to figure out how and how much Sandoval might be able to help the Red Sox over the next two seasons.

Sandoval is 28 years old and has to this point spent his entire career with the Angels. He owns a career 4.01 ERA and 3.96 FIP, and he struggled mightily in 2024 until a UCL tear ended his season in June. Sandoval underwent internal brace surgery, and he’s expected to be ready to pitch some time in the second half of the 2025 season, but that’s certainly not a guarantee. He doesn’t have great velocity, he doesn’t run great strikeout or walk rates, and he’s now a few years and a major injury removed from his best seasons in 2021 and 2022, when he ran a combined ERA of 3.17 over 41 starts and three relief appearances. So what made the Red Sox decide to take a chance on, at the most, a season and a half of Sandoval?

Just getting him out of Los Angeles is a good start. The Angels non-tendered Sandoval at the end of the season in the midst of his rehab, which is not exactly a great look. On the other hand, in Sandoval, James Paxton, Liam Hendriks, a nd Michael Fulmer, there’s now a short pattern of players choosing to do their rehab with the Red Sox. Boston clearly thinks it can help these players return to something like their best selves, and the players must believe in their medical and developmental staffs, which is a good sign. If you remember the way Sandoval carved up the USA during the 2023 World Baseball Classic, you understand that he’s capable of some serious highs.

Next, the 5.08 ERA Sandoval ran in 2024 was ugly, but his 3.87 FIP was the second-best of his entire career, which means he likely just faced some bad luck. He has done a solid job of avoiding hard contact and inducing groundballs. All of this makes him a bounce back candidate when he returns from his rehab. But there’s also something more fundamental about this move: Sandoval’s current problems make him a perfect fit for Boston’s pitching philosophy. His pitch mix is absolutely begging to be optimized. According to Statcast, Sandoval’s fastballs cost his team 12 runs in 2024. When he threw anything else, he gained his team three runs. The sinker doesn’t really sink, the four-seamer doesn’t rise enough, and neither pitch gets enough arm-side run. The pitch modeling metric Stuff+ absolutely hates Sandoval’s fastballs, rating his four-seamer a 56 and his sinker a 63. Just so we’re clear, an average pitch would be 100. Those are horrific scores, and Sandoval threw a fastball 33% of the time this season. That’s among the lowest rates in the league, but the Red Sox had 12 different pitchers who threw even fewer fastballs this season. If there’s one team that’s willing to find out just how low a pitcher’s fastball rate can go, it’s the Red Sox.

Sandoval throws both a slider and a sweeper, and those pitches grade out as excellent. His changeup is also great. It’s easy to see the Red Sox building on those two pitches and his curveball, scrapping Sandoval’s existing fastballs, and helping him design one that makes more sense. Sandoval has a high arm angle and release point, so it would make sense for him to be locating a sinker down in the zone, where a steep vertical approach angle would earn whiffs and push his groundball rate even higher, but he doesn’t seem to have been trying to do so with the Angels.  

If Sandoval just regresses to the mean and runs an ERA and FIP right around his career 4.00 marks, then that makes him a perfectly solid addition to the rotation and gives the Red Sox the bonus of adding another left-handed arm. If the Red Sox prove to be any better than the Angels at helping him become the best version of himself on the mound – and there’s ample reason to believe that they will be, both because the Angels don't set a high bar and because the Red Soc do – then they just upgraded their rotation at a pretty great price. If Sandoval can join the rotation during the second half of the 2025 season as hoped, then he’ll provide some much-needed insurance if and when a starter struggles or goes down with an injury.