Starting rotation depth has become one of the Red Sox’s biggest strengths, and Thursday the club took a step towards ensuring that remains the case in 2026.

According to a source, the Red Sox have agreed to a one-year, $800,000 deal with right-hander Cooper Criswell, who has spent the past two seasons in Boston as a depth starter and long reliever.

The major league contract is fully guaranteed. News of the deal was first reported by FanSided’s Robert Murray.

Criswell spent the majority of this past season in Triple-A but was impressive in his handful of big league appearances. He posted a 3.57 ERA in 17.2 innings, and his most notable outing came on Aug. 1, when he was called up for an emergency spot start and allowed one run over seven innings in an eventual extra-innings win over the Houston Astros.

He also posted a 3.70 ERA over 65.2 innings in Triple-A, and in 2024 he posted a 4.08 ERA over 99.1 innings in the majors, including 18 starts.

The deal came hours before the Red Sox were slated to make a series of roster moves to clear space for the nine injured players due to be activated from the 60-day injured list. Criswell, who is out of minor league options, was among the possible candidates to be designated for assignment.

Now he should enter spring training as a viable depth arm making just over MLB’s minimum salary, though he will still face fierce competition to earn a spot on the big league roster.