Fletcher appeared in United's youth team against Fulham on Monday in a 2-2 draw at Salford City Stadium.
The 29-year-old Scot has only appeared 13 times for United in almost two years, but was relieved to move a step closer to regaining a first-team spot under a manager he has not played for yet, David Moyes.
"It's been a long time so it's good to get back tonight," Fletcher told MUTV.
"I've been training for a few weeks now and the next progression is to get some match time. I enjoyed it.
"The plan was to get to half-time and see how I felt.
"Then get to 60 minutes and take it from there and, although I felt I could have gone on a bit longer, the plan was not to play more than that so I'm better sticking to the plan and not upsetting the sports science lads."
Fletcher hailed his support crew - both the club and his family - for helping him through his time off the field with ulcerative colitis.
"They've been great, especially the doc Steve McNally," Fletcher said.
"He's worked closely with me, getting myself right and back and the support from the club has been fantastic - from Sir Alex Ferguson to the new manager and David Gill. Everyone at the club. I couldn't ask for anything better.
"It's been tough. Luckily, I've got a great family around me - my wife, children, mum, dad and sisters.
"It's a great family and, if it was not for them, I wouldn't be standing here today.
"They keep me going, keep me motivated and lift me when I'm down. All these factors contributed to me standing here today on the road to recovery."
