Roy Keane Resignation - Reaction:  Alex Ferguson has admitted he is surprised by Roy Keane's sudden exit from Sunderland. Ferguson had been looking forward to welcoming his old captain to Old Trafford tomorrow as the Black Cats look to climb out of the relegation zone.

Instead former Red Devils reserve-team boss Ricky Sbragia will be in charge after chairman Niall Quinn failed to talk Keane out of quitting the Wearside hot-seat.

Ferguson was saddened at the news and feels Keane's absence is a blow to the Premier League.

"I am surprised," said the United chief. "Trying to cut through rumour and fact in football today is difficult. You are never quite sure what has happened and the rumour mill is operating at 100 miles an hour.

"But Roy was a great player here and it is a pity. We wish him well."

Ferguson has no idea when, or indeed if, Keane will return to the management ranks.

"It is difficult to say whether he will be back," said the Scot. "He is an incredibly controversial character. Every week he always had something to say about the game. He was the same as a player.

"He is such an interesting character and did a decent job up there."

Manchester City manager Mark Hughes is convinced Roy Keane will return to the game wiser and stronger.

Hughes believes his former Manchester United team-mate, who left Sunderland yesterday, has much to offer on the coaching side.

He said: "Roy is a young man and still has a great future in the game. Maybe he just needs that breathing space to refresh himself, take a step back and learn from the experience.

"He will have had his reasons for leaving Sunderland. He is a very forthright and straight guy. Once he makes a decision he sticks to his guns. That seems to be what has happened here.

"You just sensed he was going to consider his future and possibly walk away and that is what has happened."

Brian Kerr, the former Republic of Ireland manager, also expects Keane to come back in the future.

"He has a vast knowledge and feeling for the game," he said. "It's not gone too well for him as a manager but I am sure he will learn from that and I am sure he can become a very good manager in the future."

Arsenal manager Arsene Wenger believes the game will miss Keane, who he described as a "passionate" manager, but backed him to return to football.

Discussing Keane's exit, Wenger said: "It is a surprise, but I can understand that. He is a passionate man, and I regret he leaves the job.

"When you are passionate, especially at the start of this career, you suffer immensely physically. Also because he is a passionate man, there is no other way for him to be in the job.

"When you are passionate about the game, you go out of it and then come back into it because there is no other way to be happy. That is why I believe he will be back."