Hayden needed more recovery time

The world champion has been sleeping in an oxygen tent to aid the healing process prior to the first race in Qatar on March 10, and he admitted that he didn't realise just how bad his injury was at the end of last year.

"I definitely had more wrong than I thought at the time," he said. "It was quite a big operation (in late November) to take a plate our and put another plate in, and fix my rotator cuff.

"I could probably have done with a couple more weeks of rehab, but they're not really on the calendar before Qatar."

Hayden sustained the injury in the penultimate race of the 2006 season, when he was collected by team mate Dani Pedrosa at Estoril.

He rode in the season finale at Valencia with the injury, and he described the pain as the worst he has ever ridden with.

However, the American refused to have injections to ease the pain prior to his title showdown with Valentino Rossi.

"The last race - I'll be honest - it was difficult, but I'd go through it again," he said.

"I didn't get an injection as I've had those before and they mess with you. They're not the easiest of things to ride with.

"I had to be fully focused and fully concentrated on the world title, and I think that did more for me to ease the pain than any injection."