London - Toulon flyhalf Jonny Wilkinson revealed on Friday that he will be out of action for "a couple of weeks" while he nurses a groin muscle injury.
The 34-year-old English star said he underwent an "operational injection" earlier this week.
It has prevented him from training, rendering the chances of an emergency call-up for the British and Irish Lions' tour of Australia unlikely.
"I had to go in for a procedure on my groin on Monday that is going to keep me out for a couple of weeks," he told British newspaper the Daily Mail.
"It is called an operational injection, a blood replacement injection, on a torn muscle I had in my left groin and upper part of my leg. It was impacting anything I was trying to do and I wasn't really able to train during the week."
Wilkinson revealed that he had been in contact with the Lions, who tackle the Reds on Saturday, but said he had not been in touch with head coach Warren Gatland.
"I'm a long way from being 100 percent and the Lions are aware of that situation," he said.
"I haven't myself spoken to Gatland, but he's got more important and more immediate things to worry about. If that is the case (they need injury cover), then I would look forward to having any communication and there's a conversation that needs to be had. But it's on the unlikely side.
"If I do anything at the moment I will ruin my groin so I need to take it easy for a few weeks."