The 2008 signing from Roma has been gently eased back into the reserve-team picture and scored his first goal of the season in the 2-1 defeat to Blackburn last Wednesday.
Although the campaign is coming to a close, the 19-year-old is hoping to push on again over the summer after missing out on around a year of football at an important time in his development.
"It's a great feeling and I'm feeling each time better and better," he told MUTV. "It's very positive at the moment and I'm looking forward to playing more games, even though the season is nearly over now.
"We can always play better than we play the week before. The more you play, the more you feel better. I feel quite close now [to my best]. I just need games to play and to show what I can do."
The midfielder tried to analyse matches from the sidelines despite his frustration at missing out on the action.
"I tried to learn because I couldn't play physically," he added. "I tried to learn as much as possible mentally and tried to understand the game. I think that was good for me."
With Sir Alex Ferguson overseeing the reserves' development and Warren Joyce keeping an even closer watch on the players, Petrucci admits being under the microscope is a positive experience.
"That's great because it keeps you always alive," he explained. "Like you want to do things and try different things to impress them.