"With Wayne it is just that knock in the hip that he got against Blackburn," the United manager told Sky Sports on Saturday lunchtime.
"It was amazing really because Ryan Nelsen came across and whacked him in the hip and he got a foul against him.
"When you get that knock, the bruising was there and it has never cleared up.
"Last Saturday against Chelsea he was struggling badly and we can't get rid of the bruised blood.