Sunderland caretaker boss Ricky Sbragia admits the week's events have been a shock.
Sbragia will be in charge when the Wearsiders run out against his former club Manchester United on Saturday evening hoping to end a run of six defeats in seven games against the odds.
He admitted Thursday's news had come as a shock.
Sbragia told the club's official website: "It was a big surprise, I didn't know until Thursday morning.
"We knew he [Keane] was mulling things over, but the news was not expected, it was very sudden.
"We are sad to see him go. Roy Keane was part of the reason I came to Sunderland, and I wish he had stayed.
"Niall spoke to me and asked if I would take over in the short term, it's not a problem.
"Niall spoke to the players and put them in the picture. They were upset, but we have a game on Saturday and we have to be focused and prepare properly."
"When I left Sunderland to go to United, I thought it was an honour and a privilege.
"I had three great years there, I was only enticed away because of the chance to do first-team coaching, otherwise I feel I would still be there.
"I don't think Sir Alex [Ferguson] will be worried about me, to be honest. He's a great manager and great person as well.
"All I can say is when I was there, he was fantastic to me."