UFC light heavyweight champion Chuck Liddell is battling pneumonia.
Liddell, who was incoherent and momentarily fell asleep during a recent live interview on a Dallas television station, has been on a virtual nonstop promotional tour since beating Tito Ortiz in December.
The hectic pace caught up with "The Iceman," and the illness has put his planned May 26 bout with Quinton Jackson at UFC 71 in doubt.
"Chuck is supposed to be the headliner for that event," said UFC President Dana White. "This thing is growing so fast and Chuck Liddell is biggest star we have. The guy's not stopping. He was with (UFC co-owner) Lorenzo ( Fertitta) and I three weeks ago, and he was sick then."
Prior to the sickness, Liddell was still on the mend from torn ligaments in both a knee and finger and had yet to resume his normal training schedule.