The Mariners selected Milone's contract from Triple-A Tacoma on Friday, Daniel Kramer of MLB.com reports.
He'll make a spot start Friday at home against the Rockies, filling in for Marco Gonzales (paternity). Milone tossed five scoreless frames in his lone start for Tacoma this season and holds a career 4.60 ERA over parts of 12 major-league seasons. Chances are, he'll be designated for assignment after Friday's outing.