England wing Jonny May is expected to sit out the Six Nations as he requires surgery after suffering a "significant" knee injury.
May will see a specialist next Tuesday to discover the extent of the injury he sustained in Gloucester's Premiership clash with Harlequins last weekend.
The 25-year-old limped off during the 39-39 epic at Twickenham to raise concerns that he could be ruled out of the Six Nations, which England begin against Scotland at Murrayfield on February 6.
Gloucester director of rugby David Humphreys has now revealed that May must go under the knife, so it would appear unlikely he will play a part in the first tournament in a new era under Eddie Jones.
"Jonny has suffered a pretty significant knee injury that requires surgery. He's seeing a specialist on Tuesday and based on the outcome of that we will have a much clearer picture on what needs to be done," Humphreys is quoted as saying in the Gloucester Citizen.
"Most importantly it is a huge blow for Jonny to suffer an injury like that at this stage of the season but knowing him and his dedication, he will leave no stone unturned in his recovery.
"For us as a club, to lose your starting international wing takes away a huge threat. But while it is disappointing it means there is an opportunity for others and Henry Purdy will get that chance this weekend.
"Over the last 18 months he has been very good. When he arrived he would not have been expecting much game time but he played a lot last season at centre and wing and performed at a really high level and has continued to do so.
"We also have David Halaifonua so while Jonny is a huge loss and impossible to replace we do have good cover."
May's Gloucester team-mate Henry Trinder will be out for around four weeks after sustaining a hamstring injury against Quins, while Humphreys revealed that props Paul Doran-Jones and John Afoa will be out for "a few weeks" due to calf problems.