UFC heavyweight contender Derrick Lewis says he will be out four to six months following surgery on Tuesday to repair a partially torn ACL and fully torn meniscus and MCL.
"The ACL is hanging on by a thread," Lewis said on Ariel Helwani's MMA Show. "They say it's a rare tear."
Lewis, 34, fought earlier this month, losing by knockout to Junior Dos Santos on March 9.
Lewis (21-7-1) believes he tore the ACL at UFC 184 against Ruan Potts in February 2015. Potts at one point in the fight had him in a knee bar submission attempt but Lewis eventually got out. Lewis won the fight by second-round TKO. He has since fought 13 times with the injury. Fighting with a partially torn ACL for four years seems improbable, but Lewis continued to compete. He did say he believed it hindered him in some bouts.
"Especially on takedowns and especially If I had to hobble on my left leg and try to stop the takedown, it would just give out on me," Lewis told Helwani. "It would be way too weak to just stand up on."
Lewis said this was most evident when he fought Daniel Cormier at UFC 230 in November for the heavyweight championship.
Cormier continually took Lewis to the mat through the two rounds. Midway through, he got Lewis' back and sunk in the rear-naked choke to retain the belt. Lewis thinks the final outcome may have been different at full health.
"I couldn't stop the takedowns from nothing in the world," Lewis said. "And that was the reason. I didn't have any strength in my leg."