The Red Sox and pitcher James Paxton have agreed to a one-year deal, according to ESPN's Jeff Passan.
The deal is worth $10 million with a two-year club option.
Paxton, 33, spent last season with the Mariners but made only one start—completing less than two innings—before leaving with elbow pain. Shortly after, it was announced that he would have Tommy John surgery.
He previously spent two seasons with the Yankees, amassing a 16–7 record with the franchise over 34 starts, and six years with the Mariners. Throughout his first stint with Seattle, he emerged as one of the best left-handed pitchers in the American League.
Paxton will bolster a Boston rotation that includes Chris Sale, Nathan Eovaldi, Nick Pivetta and the recently-acquired Michael Wacha.
The Red Sox went 92–70 last season and eventually lost to the Astros in the ALCS in six games.
More MLB Coverage: