Schalke will be without defender Atsuto Uchida for their Champions League clash against Galatasaray next Wednesday.
The full-back has picked up a thigh injury that will keep him out of the first leg of their last 16 tie in Turkey.
"Schalke 04 will be without Atsuto Uchida in the coming weeks," reads a statement on the club's official website.
"An MRI scan on Monday [February 11] revealed the Japan international has torn a muscle in his thigh.
"The right-back was already sidelined for the Bundesliga game at Bayern Munich."
Schalke lost 4-0 to Bayern away from home on Sunday.