The Quins flier, who missed the World Cup and lasted just 15 minutes of the Six Nations, sat out this game and could be KO’d until Christmas.
Boss Dean Richards said: “There’s a possibility he might have an operation, we will wait and see what the surgeon says.”
Full-strength Ospreys needed a last-gasp Tommy Bowe score to nick a win after Quins’ stand-ins had fought back from 14-3 down with tries by De Wet Barry and Tani Fuga.
Ospreys chief Sean Holley said: “We’ve got a few bruised egos.”