For two years, Fletcher had battled to overcome ulcerative colitis, an extreme condition affecting the colon.
The Manchester United midfielder had already taken two breaks from the game in the hope of finding a way of managing the debilitating medical condition.
Nothing was working.
"I couldn't leave the house," he said.
"Simple stuff, like taking my kids to the park, going for a meal with my wife.
"The nature of the illness meant I just couldn't do it.
"There was the exhaustion side as well.
"I always believed one of the medications would work. Unfortunately that wasn't the case.
"Ultimately that was the reason I went for the operation."
Although Fletcher's surgeon was confident surgery would prove successful, the consequences of failure were laid bare.
For a 29-year-old sportsman, supposedly in the prime of a career that had already brought him four Premier League titles, an FA Cup and a couple of League Cups, it was a bleak prospect.
"There was a day in May when we said 'this is it'. Once I came out of that operation I would know whether it had worked or not.
"There were no guarantees. If the operation was not a success there was no way I would be able to play football and my everyday life would have been very difficult.
"It was very emotional. There was a lot of fear and anxiety.
"I put all my trust in the surgeon."
Liked and respected across the game, Fletcher relied upon the support of his wife Hayley and twin sons Jack and Tyler, plus the wider United community, including Sir Alex Ferguson.
There was clearly a life issue involved. But the drive to become a Premier League footballer once more was just as strong.
"I know people will say I should think about other things - and I was thinking about my children, my wife and family - but right there, right beside it was football," he said.
"I didn't want to give it up.
"I worked hard to be a professional footballer. I always have. I always kept that determination.
"I was doing this operation, not just to have a quality of life but also to get back playing football."
Fletcher achieved his aim at Villa Park on Sunday, being introduced as a second-half substitute as United beat Aston Villa 3-0.
In the increasingly cynical and cut-throat world he inhabits, this was a genuine good news story, with even the home fans offering appreciative applause.
Yet Fletcher, typically, ignored the sheer bloody-mindedness and refusal to be beaten that has typified his return to health to heap the praise on one man.
"Professor Sagar is the reason I am standing here today," he said.
"I am back to normal. I do not have ulcerative colitis. I am back playing football in the Premier League. I am just like anyone else."
Fletcher does not want pity - and he certainly does not want to be eased back in.
"I don't want to take it easy. I've done enough of that," he said.
Instead he wants to be thrust into the white heat of lifting United out of their present strife.
"It is hard enough watching the lads win," he said.
"At least if they do that you enjoy the moments.
"It is a lot more difficult when we are not."
Yet a fully-functioning Fletcher is a major weapon for Moyes to have at his disposal given the criticism his midfield has received, unjustly, in the returning Scot's opinion.
"The midfield have been harshly done by," said Fletcher.
"As soon as we lose they get the blame which I think has been unfair.
"I just want to be back playing and showing the manager what I am capable of. What I have done in the past is in the past.
"We need to go on a winning run and put ourselves in a position where people are saying we are still there.
"I want to help us win matches to bring back the success we are used to."