Kevin Lee likely won't be back in the Octagon until the end of 2020 at the earliest.

The UFC lightweight told ESPN that he has scheduled surgery to repair a torn left ACL on Thursday in Las Vegas. Lee said doctors told him he'd be out a minimum of six months, though he said he will try to "push it" and be back earlier.

"It used to mean being out a year," Lee said Tuesday. "They've gotten better with the technology and the [physical therapy], so it might even be sooner. I don't know."

Lee said earlier this month on SiriusXM that it took him awhile to get an MRI on his knee because of the coronavirus pandemic. He said he preferred not to say how the injury happened.

"Honestly, not even doing anything that was totally out of the ordinary," Lee said April 17 on The Luke Thomas Show. "I mean, I'm not going to say specifically how it happened because of insurance, you know. But, it wasn't something totally out of the ordinary. I think I may have been affected by this whole virus and s--- more than I think. For some reason, I've been overly fatigued and my body isn't feeling great. I zigged when I should have zagged and heard a pop pretty loud. Since then I'm unable to move it much."

Lee was in the main event the last time the UFC had a card. He fell to Charles Oliveira by third-round submission at UFC Brasilia in an empty arena March 14 in Brazil. After that loss -- his third in four fights -- Lee told ESPN's Ariel Helwani that he planned on taking a break from fighting. Now, the knee injury will require that.

"I didn't mean it like this, but the world works in mysterious ways," Lee said. "At this point, it is what it is. I kind of wanted the break anyway. Now it's seriously forcing me to take it."

Lee (18-6) returned to lightweight from welterweight by knocking out Gregor Gillespie at UFC 244 last November. The Detroit native fought and lost to Tony Ferguson in an interim lightweight title fight at UFC 216 in October 2017. Lee, 27, has been considered a potential breakout star in the 155-pound division.