May faces Six Nations injury woe
May was forced to come off during Gloucester's 39-39 draw against Harlequins at Twickenham after sustaining the injury while kicking the ball.
"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.
"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," Gloucester director of rugby, David Humphreys said.
England's first Six Nations fixture is against Scotland on February 6 and given Humphreys' bleak prognosis, it seems highly unlikely that May will play any part in the tournament. The 25-year-old had re-established himself as England's first choice wing.
His absence would be another blow to new England head coach Eddie Jones, who has already lost centre Henry Slade, back row forward Dave Ewers and prop Kieran Brookes to injury for all, or part, of the Six Nations.
Agence France-Presse