Newcastle winger Hatem Ben Arfa could miss the rest of the season as he looks set for surgery on a hamstring injury.
The France international, 26, returned from 12 weeks out in last week's goalless draw at Anzhi Makhachkala.
But after missing the subsequent two matches, he is facing another spell on the sidelines.
"I think he's going to need an operation on his hamstring, and it will probably leave him missing for the rest of the year," said manager Alan Pardew.
"[Next season is] the priority for him now because he's been a huge miss for us.
"He gives us that X-factor. Unfortunately for Hatem, that's the news that he didn't want to hear but as far as we are concerned, the team has responded well in his absence and hopefully, we do that until the end of the year."
Pardew insists that playing Ben Arfa in Moscow did not exacerbate the problem.
He told BBC Radio Newcastle: "That didn't have an impact on it. We felt prior to that game he had done everything he had wanted to do, the medical team gave me the full clearance, we'd done all the scans, he'd had two weeks recuperation and training."
Ben Arfa initially joined Newcastle on loan in August 2010 before completing a £2m permanent deal in January 2011.
The midfielder suffered a double leg break in October 2010.