Schalke forward Jefferson Farfan will be sidelined for several weeks after suffering an injury in Wednesday's 1-0 win against Basel.
The 28-year-old was taken off at half-time as Schalke made it back-to-back victories in the UEFA Champions League group stage courtesy of Julian Draxler's second-half strike.
And on Thursday the Bundesliga outfit confirmed that Peru international Farfan had sustained an adductor muscle injury that would rule him out of action.
The club tweeted: "Adductor muscle fibre tear. Farfan will not be available for Schalke in the coming weeks."
In stark contrast to their promising start in European competition, Schalke's domestic campaign has seen them struggle.
Jens Keller's men have won just two of their seven league matches, leaving them in 14th.