Fletcher has been sidelined for an indefinite period as he seeks to find a way of managing a chronic bowel condition.
"It's a week-by-week situation so I've not got any timescale on recovery, but the target for me is next season now," Fletcher told the Manchester Evening News. "If I can come back then, that would be great for me."
The Scotland international is trying a variety of different ways of overcoming the problem in a manner that would allow him to continue his career.
That other high-profile sports stars, including Sir Steve Redgrave, have managed it does offer genuine reason for optimism.
However, the 28-year-old has written off playing any further part in United's Barclays Premier League title bid this season.
"It's something that will never leave me but somehow you have to find a way to manage it so that I can still play my football," added Fletcher.
"I'm trying everything under the sun at the moment: diet, hypnotherapy."
Fletcher first started to experience problems last March. His absence for all but two games of the final three months of last season was put down to a virus.
However, after appearing in 10 United games this term, Fletcher felt he needed to take an extended break and revealed the true nature of his condition.
Source: PA
Source: PA