Borussia Dortmund will be without Mats Hummels for four weeks after the defender suffered an ankle injury during the side's 2-1 derby defeat at Schalke.
Hummels, 24, who had just come back from a bout of flu which had ruled him out for ten days, suffered a partially-torn ankle ligament just 30 minutes into the match at Gelsenkirchen.
With 15 minutes still left in the first half, however, the Germany international failed to signal his injury to the bench and decided to carry on playing.
""It was not like he directly signalled he could not carry on," Dortmund manager Jurgen Klopp said. "It hurt, sometimes more and sometimes less. That's why he tried to play the clock down and have a look at it during half-time."
During the break, however, his ankle had swollen and Hummels was forced to come off.
The centre-back is now ruled out for the two upcoming games against Freiburg and Stuttgart, and will most likely miss the Champions League quarter-final first leg on April 2 or 3. Hummels will also miss Germany's World Cup qualifiers against Kazakhstan this month.