Leicester Tigers director of rugby Richard Cockerill confirmed that Tuilagi had been working hard in his rehabilitation but unfortunately still required the operation.
“Manu has not been able to recover fully from the injury with rehab and had surgery yesterday to repair that,” said Cockerill.
“He had a reaction right at the end of the rehab process so it was the right thing to do. He will be out for probably three months. That’s disappointing because we hoped to have him back soon and it is a blow for him and for us.”
Matt Smith is back in contention this week after just one short appearance this season following a broken thumb and then a knock in his comeback game against Harlequins 10 days ago, while Vereniki Goneva is working his way back from a calf muscle injury and Ryan Lamb is recovering from a broken hand.
But Tigers are still without Anthony Allen, Mathew Tait and Gonzalo Camacho in the backline.
“Mat Tait is still a few weeks away with an ankle injury,” added Cockerill. “Pushing him back too early is the wrong thing to do so we’ll just manage it and be patient. Part of the surgery on Gonzalo’s shoulder did not go as well as we would have liked and he has had some more work on that.”