Woo (hamstring) threw 45 pitches and allowed two runs on a hit with two walks and two strikeouts over 2.2 innings during his rehab start with High-A Everett on Saturday, Daniel Kramer of MLB.com reports.
The 24-year-old rejoined the Mariners on Sunday, but manager Scott Servais was non-committal on whether the right-hander will require an additional rehab outing. The club wants Woo to be able to cover at least four or five innings before being reinserted into the big-league rotation, so it wouldn't be surprising if he's sent on another rehab outing to further build up his workload before being activated.