Royals’ striker has not kicked a ball in anger since December 2012 due to a career-threatening hip injury.

But despite an operation in March and months of rehabilitation, the 35-year-old is no closer to a return.

Now Roberts has admitted that he may have to concede defeat in his battle to play for Reading again.

The 2011/12 Championship title winner said: “I have never really been injured before but I think when you go through something like this at my age you start to really question how much longer you can go on.

“It’s been really frustrating. I’ve had an operation, steroid injections and time abroad. We have done everything we possibly can do and we just haven’t been able to get it to a point where I’m fit enough to play yet.

“I’ve had six or seven opportunities to try and come back and we’ve not made it through two or three training sessions.

“It’s really frustrating. I’ve never really been injured before so when you go through something like this it certainly makes you realise how lucky you’ve been.”

BBC football pundit Roberts last pulled on a Reading shirt in December 2012 in a 1-0 defeat to Southampton, then managed by Royals boss Nigel Adkins.

His last goal for the club came at Madejski Stadium in October of the same year in the crazy 7-5 defeat to Arsenal in the Capital One Cup.

On several occasions Roberts looked as though he was back on the fitness trail and eyeing a return, only to suffer yet more setbacks with his injury.

At present, he is still unable to run properly due to the pain in his hip, and the striker, who scored 169 goals in 517 appearances in a career spanning more than 16 years, fears for his future.

“I’m actually not able to get out of a jog,” he explained. “The surgeon went in, he shaved some bone away and re-attached some cartilage. It was micro-fractured, it was quite a big issue.

“I should have been back in four to five months but it has been over a year now, so it’s a frustration for everyone.

“But as a professional football player all you want to do is play football and when you’ve never been injured before you realise just what some people have been through.”

Asked if he could still make a comeback, Roberts said: “Two weeks ago I would have said ‘yes’, but after my recent breakdown I’m a little bit concerned. But we’ll go back to the surgeon and see what he says.

“In the end you can only try to come back so many times before you realise it is not going to happen. The last breakdown was a couple of weeks ago. I couldn’t get through a training session after training for two or three weeks.

“So I’ll go back to the surgeon because I’m going to need a life after football and I’m sure I’m going to need a new hip anyway. If I could play I would, but at the moment it’s restrictive.”

Roberts was one of the chief catalysts of Reading’s promotion to the Premier League in 2012. His move to the Madejski Stadium from Blackburn that January was funded by Anton Zingarevich and was a major coup for the club.

Roberts repaid that faith with six goals over the remainder of the season as Reading, then managed by Brian McDermott, enjoyed a storming finish to claim the Championship title.

And the ex-Wigan, West Brom and Bristol Rovers hitman looks back on his early days with Royals with great affection.

“The frustrating thing is that, physically, I still feel like I can do it,” he added. “When I was out there on the pitch I had a great run of form and we won promotion, something that no-one could have seen when I arrived. It was a fantastic time in my career.

“The Premier League season obviously wasn’t as good as we would have liked, but still it was a great achievement for a side that

ability-wise should have been in and around mid-table of the Championship.

“So to achieve what we did and to get to the Premier League with Reading was, in my opinion, one of the biggest achievements of my career.”