The Mariners optioned Hancock to Triple-A Tacoma on Wednesday.
Bryan Woo (elbow) is ready to return from the 15-day injured list and will reclaim a spot in Seattle's rotation this weekend, leaving no room for Hancock, who posted a 5.24 ERA and 23:11 K:BB over 34.1 innings across seven starts. He'll join Tacoma's rotation and will wait for another opportunity with the big club.