Former Manchester United player Roy Keane has said he thinks David Moyes should have been given more time.
Speaking to ITV Sport, he said: "He certainly had a hard start when he took the job. I think the chief executive didn't get the deals done that he wanted. There was a lot of negativity. He had a slow start and no momentum.
"I think it is a shame, I think he should have been given more time. I think some of the players at Man United should be ashamed of themselves, I think they have really let him down."
The Commitments author Roddy Doyle has signed a deal to work with Roy Keane to write the footballer's autobiography.
The book, called The Second Half, will be published in the autumn and is described as a blend of "memoir and motivational writing in a manner which both disquiets and reassures in Roy Keane's own original voice".
Dublin-born Doyle said: "Ten years ago I was buying something in a shop in New York and I handed my credit card to the young African man behind the counter. He read Bank of Ireland on the card, looked at me and said: 'Ireland - Roy Keane.' I'm delighted to be writing this book with Roy."
The former Manchester United midfielder said: "I am very happy to be working with Roddy Doyle on this book, and look forward to the experience."
Roy Keane has admitted he cried when his Manchester United career came to an abrupt end.
The midfielder left United in 2005 after heavily criticising his team mates during an interview with the club's in-house television station.
Keane, who is now the assistant manager of Ireland, said: "Of course I was upset: I did shed a few tears in my car for about two minutes.
"But I also told myself I had to get on with my life.
"I walked out with nothing, I had no club lined up and I was injured.
"I could have played for Manchester United easily for another couple of years."
Watch Keane and Vieira: Best of Enemies on ITV4 tomorrow at 10pm