USA midfielder Jermaine Jones is expected to miss Schalke 04's Bundesliga match against Bayer Leverkusen on Saturday evening after he damaged ankle ligaments.
The 28-year-old picked up the injury in his side's 1-0 German Cup win over second division FSV Frankfurt on Tuesday.
A scan later revealed the midfielder, who has won two caps for the USA, has torn a ligament and damaged another.
Jones also looks set to sit out Schalke's trip to Hapoel Tel Aviv on Tuesday in the UEFA Champions League.
Schalke are 16th in the Bundesliga - two places from bottom - with just six points from their first nine games.