Butt, 32, said: "I am devastated to be suspended because it's a game I would love to have played in.
However, Butt can still offer United a valuable insight into how Sunderland boss Keane will prepare his players.
He added: "Keano will relish this occasion because of the way he is and the way he was as a player. He likes the aggressive part of the game and I'm sure he'll be looking forward to it."
Butt and Keane have stayed in touch and are still near-neighbours in Cheshire.
The Toon ace said: "He was the most driven player I ever played with - and I played with a lot of driven people. The way he stood up and spoke and trained was always about drive.
"I have spoken to the lads who work under him now and they say he is exactly the same as a manager."