In just his second match back since returning from a thigh injury, Manuel Lanzini was forced to leave West Ham's meeting with Liverpool in the 39th minute.
The issue appeared to be a recurrence of the problem that sidelined him for a month until his return to action last Monday against Southampton, and Lanzini hobbled off to be replaced by Pedro Obiang.
West Ham was up 1-0 at the time of the Argentinian's withdrawal, and the winger was characteristically involved in the tie, hammering the post with a fine effort on 16 minutes.