Manchester United manager Sir Alex Ferguson has described Chris Smalling's broken metatarsal as "bad news".
The 21-year-old defender is expected to miss at least 10 weeks of action after picking up the injury in training on Wednesday.
"It is a bad blow for the boy because he missed the end of the season with a groin injury," said Ferguson.
"We thought we had him on the right road to recovery and he gets another injury, which is bad news. He got it in training on Wednesday, was diagnosed on Thursday and we decided to operate last night (Friday).
"Normally with a metatarsal you are looking at between 10 weeks and three months. He is only 21. He is young. Hopefully he gets over it."
United continued their pre-season campaign on Saturday with a 1-1 draw against Ajax Cape Town.
