The Mariners selected Chargois' contract from Triple-A Tacoma on Sunday.
He'll join the Seattle bullpen as a replacement for starter Ljay Newsome, who was placed on the 10-day injured list after exiting his start against the Rangers early Saturday due to right elbow inflammation. The 30-year-old Chargois, who owns a 4.58 ERA across 85 career MLB appearances, is expected to work mostly in lower-leverage spots.