Margevicius was optioned to Triple-A Tacoma on Sunday.
Margevicius underwent surgery for thoracic outlet syndrome last summer and won't make Seattle's Opening Day roster. The 25-year-old southpaw appeared in eight big-league games in 2021 and allowed 11 earned runs with a 12:7 K:BB over 12 innings. He should be in the mix for a call-up when the Mariners require a spot starter.