Newcastle manager Steve McClaren admits striker Emmanuel Riviere may require surgery on his injured knee.
Riviere returned home early from Newcastle's pre-season tour of the United States after taking a knock to the knee in training.
The Frenchman was left out of the Magpies' season-opening draw against Southampton on Sunday because of the injury and McClaren concedes the 25-year-old may need an operation.
"I think Manu Riviere's knee was painful after training so he might have to have surgery," McClaren told the Newcastle Evening Chronicle.
"We are investigating that."
Riviere scored just one goal in 23 league appearances last season following his £5million move from Monaco.
Source: PA
