AC Milan may have to make do without the services of Alexandre Pato for the foreseeable future.
The Brazilian international made a return to the Milan squad during yesterday's 3-1 loss to Barcelona following a two-year battle with a thigh injury.
However, the 22-year-old only spent 14 minutes on the pitch before he was forced to limp off with a muscle complaint.
"He felt pain in his thigh again," coach Massimiliano Allegri told reporters. "The medical staff will have a look at it.
"It's a serious problem if he's picked up yet another injury. He's been struggling for two years now."
Pato has been limited to 16 appearances in all competitions this season.