UFC interim lightweight champion Tony Ferguson is currently on the sidelines nursing a knee injury. It was an ailment that forced him out of his scheduled UFC 223 title fight against Khabib Nurmagomedov.

Along with a graphic photo of his stitched up knee that he posted on Instagram, Ferguson promised to not let this mishap deter him from his goals. But for former opponent Kevin Lee, “El Cucuy” might not be able to fully bounce back.

“I feel bad for the guy, I really do. I don’t think he’ll ever be the same coming off that one,” Lee told Joe Rogan during a recent appearance on the JRE MMA Show podcast.

“That’s huge, especially at 34 (years old), to try and come back off that. And it kind of sucks for me, too, because I think I fought the best Tony Ferguson that you’re gonna see, period, really.”

As the current interim champion, Ferguson is expected to be one of the fighters who will be next in line to fight for the undisputed title. Lee, however, believes the compromised knee could be a mental hindrance for Ferguson moving forward.

“He’ll come back and he’ll still beat great guys. He’s still gonna do very good. But I don’t think he’ll be the same,” Lee said.

“I think the body can come back, it’s just I don’t know if his mind will let him be as free (because) that was one of Tony’s biggest assets,” he added. “He just does whatever the f—k he wants, and now, when he gets back in there, is he gonna be thinking about his knee? Even if that’s at the back of your mind, it’s limited to that type of style that he likes to fight.”

Lee (17-3, with ten wins by stoppage), is fresh off a fifth-round TKO win over Edson Barboza on Saturday night in Atlantic City.