"During the close season I started to do some running in the gym and I was fine. Then I stepped it up to do some running outside and started to feel a pain in my groin," he told the official website.
"I came in the day before we were all due back and Prav had a look at it and said that I'd re-inflamed the ligament that I'd damaged in February.
"So I went for an injection straight away, hoping that it would settle down quite quickly but it hasn't healed 100 per-cent yet, despite having gone for a second injection on Tuesday."
"That's the last injection I can have now as you're only allowed three a year and of course I had the initial one in February.
"It's now a case of making sure that the groin is fully healed as neither myself nor Prav want me to come back too early and risk damaging it.
"It's an impossible situation as I don't want to risk damaging it further, but equally I'd like to get some games under my belt before the season starts.
"Now with the signing of Paul Jones, competition for places is at its strongest. I wouldn't want to lose my place, bearing in mind how well Jonesy played when he came in last year."