Newcastle full-back Davide Santon will be out for at least a month after damaging his knee in training.
The former Inter Milan star, who completed a £5m move to St James's Park last month, is yet to kick a ball for the Magpies.
A statement on the club's website said that the 20-year-old "has undergone a scan on his right knee".
Magpies boss Alan Pardew was reportedly ready to hand the defender his debut in Tuesday's Carling Cup tie at Nottingham Forest.
“It’s a worry. It looks like it could be a cartilage and it’s not something you want when he’s just come into the building," Pardew said.
“Maybe we’re looking at a month out. He’s going to have to get it cleaned out, it’s keyhole surgery nowadays which is a quicker operation but it will certainly mean at least four weeks out.”
Santon has a history of injury problems but Pardew insisted that the Italian passed a "thorough" medical on his arrival to Tyneside.
“Davide has had a few injuries in the last couple of years which isn’t ideal," he added.
“He’s been through a really thorough medical and he’s a little bit unlucky as we’re only a week or so on from the medical. He trained today and trained well. It was just when he came off, he complained a little bit and we’re erring on the side of caution with him.”
Newcastle will confirm the results of the scan this afternoon (Friday).
