Sewald was reinstated from the paternity list Monday.
Sewald was away from the team since Thursday, but he'll rejoin the active roster and take the place of right-hander Yohan Ramirez in the bullpen. The 31-year-old has taken on a setup role since the Mariners traded for Diego Castillo at the end of July, and he's recorded two holds with a 5.40 ERA and 0.60 WHIP in 6.2 innings across six appearances since then.