The Reds striker, currently on international duty with the Three Lions, was sidelined for much of the early part of the season after suffering a gashed thigh in the 3-2 win over Fulham in August.
Now, having completed some extensive work in the gym and on the training pitch, Rooney has returned to action in rude health and hopes to reap the benefits in the coming months.
“When I came back in pre-season I wasn't out of shape,” Rooney told reporters at The FA's new St George's Park facility. “I was probably not as fit as I could have been, whether that's because I didn't have the time to get the training in I don’t know.
“I got injured since but I have worked hard. To be honest it probably helped me to get fit getting injured. I feel good, I feel fit, I feel ready to go and play.”
Since returning to the first team fold, Rooney has been deployed in a much deeper, more creative role by manager Sir Alex Ferguson, allowing the 26-year-old to enjoy more input and influence on matches.
The decision has so far proved to be a masterstroke and, as a result, the United star looks set to feature in a similar role for Roy Hodgson in England’s Wembley meeting with San Marino on Friday.
And although the new role is more taxing on the body, drastically increasing the average distance covered by a forward player, Rooney is loving his new position.