Borussia Dortmund captain Sebastian Kehl is an injury doubt for Wednesday's Champions League match at Napoli after twisting his ankle in training on Sunday.
The 33-year-old landed heavily on his right ankle after a training ground collision and had to be helped off after the joint quickly became swollen.
The defensive midfielder was taken away for treatment and Champions League finalists Dortmund are waiting to see how bad the injury is.
Centre-back Neven Subotic suffered a bruised foot in Saturday's 6-2 rout of Hamburg which left Dortmund top of the Bundesliga as the only team with a 100 percent record after five games.
Attacking midfielder Henrikh Mkhitaryan, who scored Dortmund's second goal against Hamburg, suffered a knee knock, but coach Jurgen Klopp has said both players should be fit to play in Naples.