Article: Breaking Down the Boston Bullpen: Part 3

[Amrit Brown]

In part one of this five-part series, we looked at the best of Boston's relievers. In part two we looked at the bulkiest. Now we look at the bottom.

In part one of this series we focused on the best of the bunch, and in part two we focused on the pitchers who provided the most innings. Today, we look at the pitchers who struggled the most.

Luis García
The Red Sox traded for Luis García at the deadline, giving up first baseman, Niko Kavadas, outfielder Matthew Lugo, and pitchers Yeferson Vargas and Ryan Zeferjahn. What made the 37-year-old rental worth a four-for-one swap? He was a veteran running a 3.71 ERA at the time. All the same, he was not what the doctor ordered. It was a cruel summer for the righty, as he posted an 8.22 ERA in 15 1/3 innings for the Red Sox. His performance kept him out of high-leverage innings down the stretch and helped seal the team’s fate. Some of that start change was luck, but his FIP also jumped from 3.69 to 5.06, indicating that the underlying numbers weren’t great either.

García added a cutter in 2024, but he threw it less than 2% of the time and pitch models were split on it. a pitch that ranked below league average in Stuff+. His fastball velocity dropped by 1.2 mph from 2023 to 2024, and his groundball rate, hard-hit rate, and barrel rate were all the worst they’d been since 2021. García is a free agent this offseason and it’s hard to imagine him returning to Boston after last year’s performance.

Bailey Horn
Bailey Horn made his MLB debut with the Sox in 2024. His rookie year did not go as planned, as he pitched 18 innings over 18 appearances with a 6.50 ERA and a 7.00 FIP. He walked a brutal 11.4% of the batters he faced. The problem wasn’t his control. He actually hit the zone an extremely high 58% of the time. The problem was that his 21% chase rate was one of the lowest in baseball. There’s nothing wrong with missing the zone as long as you can get batters to swing, but Horn wasn’t able to do so. Unfortunately, hitting the zone didn’t work out great for him either. He gave up five home runs over his 18 innings. Some of that is bad luck over a very small sample size, as nearly a third of the fly balls he allowed ended up learing the fence, but the underlying numbers were’t pretty either. Stuff metrics loved Horn’s sweeper, but they didn’t trust any of his other pitchers, even his 95-mph fastball. Horn will not be joining the Sox in 2025. He was claimed by the Tigers off waivers in November.

Lucas Sims
The Red Sox acquired Lucas Sims the same day as García, trading him to Cincinnati for single-A pitcher Ovis Porters. The 3.57 ERA that Sims ran over 35 1/3 innings with the ballooned to 6.43 in 14 innings with the Red Sox. Unlike Horn, Sims did struggle to hit the strike zone, and of the 402 pitchers who threw at least 40 innings, his 14% walk rate was the seventh-highest in baseball. He also struggled to keep the ball on the ground. In that same group, his 28% groundball rate was the fourth-lowest. Sims also went on the IL in August, which definitely did not help him get comfortable in Fenway. On the bright side, had a 31.3% hard-hit rate and 85.4 average exit velocity, some of the best numbers in baseball, and that’s not a new development for him. Over his career, he’s been able to have success when he’s missed more bats, racking up some strikeouts to go with his weak contact. It just didn’t work out that way in Boston. Sims entered free agency after the season and is unlikely to return to the Red Sox.

In some pretty small sample sizes, things got ugly for García, Horn, and Sims in 2024. They had many Sox fans peering through their fingers and asking “Is it over now?” every time Alex Cora called them out to the mound. García and Sims were supposed to boost the bullpen and turn around a summer skid and Horn was supposed to add another solid lefty; it didn’t work out that way.

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