Analysis: George Caulkin I Roy Keane: how his regime unravelled | £80m wasted? Keane's transfer hits and misses | Tony Cascarino: Keane should have kept quiet over Sunderland future I Allardyce favourite to replace Keane | Video: 'Sometimes the players need to lift themselves'I Who should be the next manager of Sunderland?

What are the main reasons behind Keane's departure?

I think there are a number of factors behind this. Of course the run of games, six defeats in the past seven games, that has taken them into the relegation zone, is a major reason. But more than that, it was about whether Keane was still getting his message across to his players, and from what has happened this morning it is clear it was felt he wasn't able to do that.

Was this Keane's decision?

No I don't think we can say that just yet. The past few days have been spent taking stock. We know he had been thinking about whether he was the man to take the club forward, but equally the club had asked him whether he could adapt his style of management to work with the players he now has at his disposal.

Working with a personality as unpredictable as Keane’s is not straightforward and although he was asked to curb his authoritarian approach in an attempt to get the best out of the players, especially the foreign imports, it seems he wasn't able to do that. So for now we can't say this decision was purely down to him.

Where does Keane go from here?

He is one of football's most volatile characters and although he was being spoken about as a future Manchester United manager just a few months ago that may change now. It is difficult to see how he will ever be given a better chance as a manager than he was at Sunderland. Keane has only ever had the support of his board, he has been given everything he asked for and been allowed to build the club in his own image without interference.

But it seems hard to believe that anyone would now be prepared to give such a level of control anywhere else.

Who could replace Keane at Sunderland?

Sunderland spoke to Sam Allardyce before they appointed Keane, and with him being out of work and a former Sunderland player he will be the bookmakers' favourite. It is too early to start speculating, but Allardyce is an obvious candidate.

Does this development mark Sunderland out as realistic relegation candidates?

Well, they will be expected to lose against Manchester United on Saturday. But after that they have pivotal matches against West Bromwich Albion, Hull City and Blackburn Rovers. What is stacked in their favour is the quality and experience of the players they have at their disposal.

If a manager can come in and get the best out of this squad I am confident they have enough to steer themselves away from trouble.