The Mariners optioned Hancock to Triple-A Tacoma on Sunday, Shannon Drayer of SeattleSports.com reports.
The move implies Luis Castillo (hamstring) will be able to return from the 15-day injured list to make a start this coming week. Hancock has been a serviceable sixth starter for the Mariners this season, posting a 4.72 ERA and 1.30 WHIP in 11 starts (55.1 innings).