Woo (shoulder) threw his normal between-starts bullpen session Thursday, Zach Sweet of MLB.com reports.
Woo had to leave his last outing versus the Astros on Sunday after 75 pitches because of right shoulder soreness. However, Woo and the Mariners downplayed the issue at the time, and he appears in line to make his next scheduled start Saturday against the Cubs, provided he bounces back from Thursday's mound work with no hiccups.