Does Reunion With Southpaw Make Sense For Red Sox?

Much of the focus for the Boston Red Sox this offseason has been on the top of the market. Big bats such as Alex Bregman and Ketel Marte have dominated the headlines. There’s still work to do in other areas of the roster, though.

While it isn’t flashy, left-handed relief is still an area of need for the Red Sox. As it stands, there isn’t much in terms of southpaws on the roster outside of Aroldis Chapman, who won’t be matching up with lefties in the middle innings. Jovani Moran is the only left reliever on the roster with major league experience. Payton Tolle, Connelly Early and Kyle Harrison are options, though the team will want to maximize their value by developing them as starting pitchers.

Boston was connected to both Seranthony Dominguez and Danny Colulombe earlier this offseason. Each remains unsigned at this point, but there will likely be competition for their services. Former Red Sox reliever Cam Booser is a free agent and is an under-the-radar option to bolster the bullpen.

On the surface, Booser’s numbers are uninspiring. He registered a 5.52 ERA in 31 innings for the Chicago White Sox last season. At the same time, the under-the-hood numbers paint a better picture.

Left-handed hitters hit just .196 against Booser and struck out 29% of the time. He used a four-seam and sweeper combination, with each pitch returning a swinging strike rate over 17%. Command was an issue for Booser, though; he walked over 14% of lefties. The White Sox slashed his cutter usage against them, which was a high strike rate pitch for him during his time with the Red Sox. It was hit hard in 2024, but a shape change kept hitters off of it in 2025. Bringing the cutter back into the mix in 2026 could help return the walk rate to normal levels.

He struggled against righties in 2025, but had success against them previously. His fastball swinging strike rate plummeted from 14% to 7%, which could be due to pitching more to the outside part of the plate. He throws hard at about 95 mph, more than enough to survive in short appearances.

Booser was traded to the White Sox in December 2024 in exchange for Yhoiker Fajardo. Fajardo quickly rose in the prospect rankings and looks to be a promising young pitcher. Booser isn’t the flashiest option for the Red Sox, but he’s a low-cost one that could help the team spend elsewhere.