Schreiber was claimed off waivers by the Red Sox on Thursday.
Schreiber was designated for assignment by Detroit on Friday, but he'll join the Red Sox to begin spring training. The right-hander made 15 relief appearances for the Tigers in 2020 and put up a 6.32 ERA and 1.47 WHIP over 15.2 innings. He should compete for a role as a middle reliever in Boston's bullpen ahead of the 2021 campaign.