Back-row forward Earl hobbled out of the warm-up of Saracens’ 38-10 thrashing of Harlequins at The Stoop on Saturday.
Fears have been raised that the 25-year-old could be out of action for as long as three months, leaving him a doubt for the start of the Six Nations.
But Saracens boss Mark McCall hopes that Earl could be back in action in early January.
Earl was England’s stand-out star of the World Cup, excelling at No 8, and will be wanted back in action as soon as possible for both club and country.
“Ben had a minor knee procedure this morning,” said Saracens rugby director McCall.
“So we anticipate he’ll be out between six to eight weeks. It’s his medial meniscus.
“I think he’ll be playing the month of January, and that would be ample time for Ben to get in. He’s had a busy time, he had a lot of minutes in the last few months, so to have six weeks of not playing rugby might actually be good for him in the long-run this season.
“Overall, if he can be back playing by then, that would be a good result.”
A hopeful outlook on Earl was tempered by bad news for centre Alex Lozowski, whose own knee problem has been confirmed as anterior cruciate ligament damage.
Lozowski could be looking at a typical recovery time in the region of six months.
“Alex Lozowski got an ACL injury at the weekend, and he’ll be out for a lot longer than Ben will be,” said McCall.
“Alex will have an operation next Wednesday. So it’s a real shame for him. He’s been such a reliable, consistent good player for us since he arrived to be honest.
“I can’t remember the last time he was injured. So to get an injury like this is never easy. As far as I know it’s as clean an ACL injury as you can get, which is encouraging in terms of how quickly and how well he’ll come back from it.”