Roy Keane admits he should never had made his move to Celtic at the end of his career after being left needing painkillers just to get through training.

The Man United icon won the Premier League and Champions League as a player at Old Trafford, making a name for himself as one of the game's most fearless midfield battlers. He was announced as a Celtic player in December 2005 but with his career winding down, a shock Scottish Cup defeat to Clyde on his debut was only the start of a move the pundit wishes he hadn't made.

He retired from football on medical advice after 10 appearances the following summer, and the 52-year-old has revealed a conversation with then-boss Gordon Strachan that provided clarity on his retirement. Keane admits he wasn't showing the best of himself in green and white as pain started mounting. He told Stick to Football: "I was 34 when I finished. But I should have retired when I left United. I even lost a bit of the love for the game after that.

"I went up to Celtic but my hip was really at me, painkillers for training. I tore my hamstring two or three times up at Celtic. I was commuting. I still had a year left on my contract and I rang Gordon.

"I went to see the hip specialist who said the longer you play on, the worse damage... he was talking about when I retire, about quality of life.

"I rang Gordon Strachan about what do I do. I had gone up there and kind of embarrassed myself, I wasn't really doing the business. I'd said I am finished but losing sleep before I rang him, as soon as I put the phone down I had closure on my career. I had no hesitation, I wouldn't say relief, but something lifted off me. When you have had injuries it beats you up."