Tony Ferguson has confirmed he will undergo surgery on Monday after tearing his lateral collateral ligament.
The UFC star was forced to pull out of his lightweight championship showdown with Khabib Nurmagomedov just six days before the scheduled fight.
Ferguson suffered a freak accident during punditry work and was subsequently stripped of his lightweight interim title.
It was the fourth time a fight between Ferguson and Nurmagomedov has been called off. Ferguson posted on his Instagram he would be having surgery on Monday morning.
Ferguson is expected to be sidelined with the knee injury for several weeks, and it is unclear if the UFC will try and re-book the Nurmagomedov clash.
UFC president Dana White was adamant after the latest set-back he would never make that fight ever again, and it seems fans may never see Nurmagomedov and Ferguson collide in the octagon.
Ferguson is also a potential opponent for Conor McGregor, although the UFC stars future is now in serious doubt after he was arrested and charge in New York.
McGregor has been charged with assault and criminal mischief after attacking a bus carrying UFC fighters last Thursday.
Nurmagomedov was McGregors intended target, but the Irishmans actions led to two other UFC fighters being injured, forcing the UFC to cancel three UFC 223 fights.
Ferguson reacted angrily to being stripped of his interim title and had to watch from afar as Nurmagomedov became the undisputed champion on Saturday.
Nurmagomedov beat Al Iaquinta at UFC 223 to claim the belt that was previously owned by McGregor.