Newcastle defender Mike Williamson will miss the remaining three games of the season after breaking his arm in training on Thursday.
Williamson, who has lined up alongside Fabricio Coloccini at the heart of the Magpies' rearguard for much of the campaign, was due to undergo surgery on Thursday afternoon.
A club statement said: "Newcastle United can confirm that defender Mike Williamson broke a bone in his forearm during training this morning.
"He will be having an operation this afternoon and will be out for the rest of the season."
Winger Hatem Ben Arfa is also unlikely to play again this season after suffering a setback in training.
Manager Alan Pardew had hoped to involve the 24-year-old France international in the final three games of the campaign, but has admitted that may not now be possible.
Pardew said: "We think that's probably not going to happen now. He's had a little setback. That's what happens when you come back from that sort of injury, so I think that's unlikely."