"Wayne Rooney will play tomorrow," Fergie told the press on Friday.
"He has to start a game to see how far advanced he is.
"We could have been tempted to use Wayne at Derby but we felt the extra few days' training would help him.
"He had a little setback which wasn't terrible but it was enough to keep him off for a couple of days.
"Then we had to bring him back into real training to make sure he was 100 per cent fit.
"Thankfully he came out of Wednesday with no reaction."