As well as meaning that the World Cup winner is likely to miss his country's Six Nations campaign, the seriousness of the injury will give the most-famous face in English rugby little time to press his claims for a place in Ian McGeechan's 35-man squad to face the World Champions in May and June of next year.
"I saw my knee specialist and he confirmed the recovery time for my left knee is likely to be five months," the 29-year-old former England skipper told The Times.
"It is no secret that this does not augur well for my hopes for England or the Lions later in the summer but I will not rule anything out.
"If it doesn't happen, it doesn't happen, but it will have been worth striving for."
Although Wilkinson will require more surgery later this season, he has allayed fears that the injury will not result in his early retirement.
"This is the most debilitating injury I've had.
"But I'll nail one thing: the idea this might be the end of my playing career. Forget it. It's not a consideration."