Sir Alex on Rooney's injury:
"We'll just have to wait and see how his ankle is tomorrow (Wednesday). Hopefully it's not too serious. He might be doubtful for Saturday (Chelsea) but we don't know for sure."
Rooney left the Allianz Arena walking on crutches wearing a protective boot.
Ankle and foot injuries are not new to Rooney as a few months before the 2006 World Cup he suffered a fracture to the base of the fourth metatarsal. He was able to recover quite quickly because it was an atypical fracture.