It will be quite some time before UFC heavyweight champion Brock Lesnar returns to fighting. In fact, he may never fight again.

Lesnar, 32, went to his property in Canada last week to get some rest while battling mononucleosis. During his stay, Lesnar collapsed and was rushed to a hospital for a battery of tests to determine what was wrong with him. While undergoing tests, doctors discovered another illness in addition to mono.

Dana White revealed the news today in the post-fight press conference for UFC 105 in Manchester, England.

"I am worried about it," White said. "I can't really talk about it right now, but he is in rough shape. He's in really bad shape. I'm actually probably going to fly to go see him, and we're going to probably have to do some stuff to take care of this guy. He is not well, and he's not getting any better."

Lesnar requested that White not reveal the exact nature of his illness, but White did state that it was not AIDS or cancer.

White said that he's not sure what they'll do about the heavyweight title situation.

"If it's a long wait, we're going to have to do something," White said. "We're going to have to. The last thing I ever want to do is strip a guy who won a title. That's the last thing I want to do. I don't know if we'll have to do an interim or what we'll do to fix it."

White is flying from England to Minnesota and will be working to get Lesnar admitted into the Mayo Clinic or another hospital facility of equal stature.

Heavy.com has learned that reports indicating that Lesnar will be forced to retire are premature.