Swansea defender Marcos Painter faces a lengthy spell on the sidelines after suffering a cruciate knee ligament injury.
Painter sustained the injury during the 3-0 weekend win over Southampton as he was forced to be stretchered off.
Scans have confirmed Swansea's worst fears and Painter now faces up to six months out of action.
"Unfortunately it's turned out to be the worst-case scenario for Marcos," said Swans boss Roberto Martinez.
"He has been in great form and it is a heavy blow for us, but all he can do now is challenge himself to come back fit before the end of the season.
"It's a test for our squad, too. We have got other options and we need to make sure whoever comes in takes their opportunity."