UFC heavyweight champion Brock Lesnar is suffering with something related to an intestinal disorder and will probably require "major surgery," UFC president Dana White said in a report Monday on TMZ.

Lesnar, who twice pushed a fight back recently due to a bout with mononucleosis, is facing a far more significant illness that is potentially career-threatening.

"There's a possibility Lesnar will never fight again," White told TMZ.

White plans to have Lesnar transferred to the Mayo Clinic in Rochester, Minn. for further diagnosis and treatment.

During the UFC 105 post-fight press conference, White declined to specify Lesnar's illness to respect the star's privacy, but did state that Lesnar neither has cancer nor AIDS.

Lesnar was scheduled to defend his belt against Shane Carwin at UFC 106 on Nov. 21 but the fight was postponed when Lesnar came down with mono. Both fighters received bout agreements for UFC 108 on Jan. 2, but that was postponed indefinitely earlier this month when Lesnar remained unfit to train.

"I can't really talk about it right now, but he is in rough shape. He's in really bad shape," White said Saturday. "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."