Sewald was reassigned to minor-league camp Friday.
Sewald was a non-roster invitee during spring training after signing a minor-league contract with the Mariners in January. However, the right-hander was unable to secure a spot on the major-league roster after he posted a 9.64 ERA and 2.36 WHIP in 4.2 innings during five spring appearances. Sewald will likely begin the year at Triple-A Tacoma.