Newcastle United striker Aleksandar Mitrovic could face a spell on the sidelines after picking up a knee ligament injury.
The Serbian did not travel with the Premier League squad for a warm-weather training camp in La Manga and head coach Steve McClaren confirmed he will need "a couple of weeks" to recover.
"He's got a knee injury," McClaren told nufcTV, as he prepares his team for a friendly game with Lillestrom this weekend.
"We're only bringing players here who can actually train over the next four days, and play in the game on Saturday.
"Mitro has a medial ligament injury, so it could be a couple of weeks - we're hoping not too long."
The news comes as a blow for a Newcastle side who remain in the relegation zone following their 5-1 thrashing by champions Chelsea last week.
McClaren hopes to use the coming days to boost the morale of his squad before they resume their Premier League survival battle with a trip to Stoke City on March 2.
"It's important to come here and be together and around each other after the disappointment of the weekend," he said.
"The previous week, we had a great week and everyone was buoyant. All of a sudden, you lose at Chelsea and you're back down again.
"It's one step forward and two or three back. We made three bad mistakes in the first 15 minutes and you can't do that against Chelsea. They punished us and it was difficult to come back.
"So we've got to gather our forces again and play like we have done against the likes of West Ham, West Brom and Manchester United at home, and get back to that form."