The Red Sox added Criswell to the active roster to serve as the 27th man for Saturday's doubleheader against the Guardians.
Since being sent down to Triple-A in early April, Criswell has turned in a 0.82 ERA and 0.91 WHIP across 11 innings alongside a 16:3 K:BB. He'll help the Red Sox's bullpen get through Saturday's twin bill but is likely to head back to Worcester after Game 2 is finished.