Owen Hargreaves admits he played on through the pain when he shouldn't have done during his first season at United. The Reds' midfielder is on the comeback trail after his 18-month injury nightmare, but has revealed he still needs painkilling injections to get him on the pitch. And although the 29-year-old, who has undergone surgery on both knees to try and cure a tendonitis problem, doesn't blame anybody for the pain he has suffered since that debut season, he says he shouldn't have been on the pitch. Hargreaves signed for the Reds for £18m from Bayern Munich in the summer of 2007 but arrived at the club with the tendonitis problem already surfacing. It was only when he finally decided to seek help from the renowned specialist Dr Richard Steadman at his clinic in Vail in Colorado that the full extent of the severe damage was revealed. The surgeon told the England World Cup ace he'd not seen a pair of knees in a worse state in his 35 years of practice. "In my first season at United I had the pain and was able to play through it, but basically I shouldn't have been playing," said Hargreaves. "In the end, the pain was just too high and I had to have surgery. "I wouldn't wish it on anyone. There were massive operations, very severe, and a lot of the treatments since have been slightly experimental. You have to try to find what works. "It's difficult to describe the pain. It's just pain. At least the surgery did its job because before the operation my tendons obviously weren't in the greatest condition. "I would like to progress from this point even more. Hopefully I will be fit this season, and going forward I will be able to play another six, seven or eight years." Hargreaves made his return with a 45-minute run-out for the Reserves last week, and could step that up tonight when the Reds face Burnley Reserves at Accrington. "I wouldn't say I am pain free and I don't know if I can play through it," said Hargreaves. "My training has improved over the last few weeks and that is a very positive sign for me. I believe that it will continue to improve and progress. "But I am still in the process of getting some injections to try to manage the pain because if I didn't have any pain I would have played at the beginning of the season. "It's about training, getting these injections and trying to go forward." Although Hargreaves admits there have been times over the last 18 months when he thought he would never play again, he is now determined to play on. "It is only human to think that way (about quitting)," he admitted. "The longest injury before that was when I broke my leg at Bayern Munich and I was out for a couple of months. "Football is a physical game and injuries are part of it. But I could never imagine having one that has impacted on me so much. I thought - everyone thought - I would be fit for the start of the season. It didn't materialise. "It has been a pretty humbling experience and I am sure many people doubted me, but anybody who knows me knows that what I set my mind to, I get. "I had better get there. I am not coming back to just be one of the guys and fill a spot. "I have never been that way and, if that was case, I would rather walk away. I am coming back to have an impact."