Newcastle midfielder Kieron Dyer has revealed his regret over the sacking of former Magpies boss Sir Bobby Robson.
Dyer fell out with Robson after refusing to play on the wing and the 71-year-old was sacked in August.
"When I think about it, I feel like I betrayed Bobby. That's the worst thing about it," Dyer told the Independent.
"He treated me like a son and I let him down. I must take some responsibility for him getting the sack. I regret letting him down so much."
Dyer was asked to play on the right of midfield against Middlesbrough on the opening day of the season after Newcastle had been badly hit by injuries.
But after his refusal the club made a poor start to the season and Robson lasted just another 16 days in the St James' Park hotseat.
"I'd spent the previous season playing out of position - filling in wherever there was a gap, it always seemed it was me who did everyone a favour," added Dyer.
"Bobby knew I was frustrated but I should have just played that game. He stuck by me through everything and he even tried to defend me after the Boro game.
"He told the press I had a tight hamstring, he tried to shield me and when I think about that, how I let him down, it's the biggest disappointment of of my career.
"I'll have to live with that feeling for the rest of my life."
Meanwhile, Magpies chairman Freddy Shepherd has told BBC Radio Five Live Alan Shearer would not have agreed to play on next season had Robson still been in charge.
"I'm not being disrespectful to Bobby, but I don't think Alan would have stayed.
"With Graeme I think they're sort of soul mates and I think that's one of the reasons he's decided to stay on another year."