"Nemanja's been taken to hospital and he has concussion so they're giving him some tests. John O'Shea has just got a dead leg. He'll be OK in a couple of weeks I'm sure."
The United manager also revealed that both Darren Fletcher and Owen Hargreaves are making good progress with their recovery from leg and knee injuries respectively.
"Hopefully Darren will be back soon," said Sir Alex. "He starts full training on Monday which is good news.
"I hope Owen Hargreaves will be available in two or three weeks time as well."