CAMP VERDE, Ariz. - Tommy Morrison says an MMA fighter is no match for a trained boxer.

And he plans prove it Saturday night in a cage outside a casino in northern Arizona.

Morrison, the former world heavyweight champion who tested positive for HIV 11 years ago, will make his mixed-martial arts debut in an unsanctioned bout at Cliff Castle Casino against John Stover, a 325-pounder who outweighs Morrison by more than 100 pounds.

"I'm just going to walk out and hit him on the chin," Morrison said at a news conference Thursday night. "I'm concerned about killing someone. I'm not kidding.

"We're trained to hit a moving target. These guys run in with their chin hanging out."

The brash-talking Morrison remains a boxer at heart, and he hopes for another shot at the heavyweight title. But for now - and for an undisclosed sum - he's venturing into the wild world of MMA.

Morrison, who said he weighs about 213 pounds, said he has done little MMA training, although he expressed concern about wearing four-ounce fingerless gloves.

"I'm a little nervous about that - not for myself but for the other guy," Morrison said. "To me, it just seems like someone signing up for assassination class. He must be out of his mind."

Stover didn't attend the news conference, and there were questions about whether he would show up for the fight, which will be held about 90 miles north of Phoenix.

"I'm sure he's on his way," promoter Peter McKinn said. "If it was me, I wouldn't be on my way."

Morrison's MMA venture is the latest chapter in the colorful life of the man who beat George Foreman, stopped Razor Ruddock and fought Lennox Lewis. Morrison seemed on his way to a big-money showdown with then-champion Mike Tyson when he tested positive for HIV before a 1996 tuneup bout in Las Vegas.

The 38-year-old Morrison has been attempting a comeback after an 11-year retirement following the discovery that he was HIV positive. Morrison claims he has taken several HIV tests during his comeback bid and all have been negative.

"They've been telling me I've been dying for 11 years," said Morrison, who became emotional as he discussed the subject.

McKinn said Morrison would not have to take a blood test for the MMA fight. The bout is being held on the Yavapai-Apache Nation, outside's the state boxing commission's jurisdiction.

The fight is not part of Morrison's three-year contract with Top Rank. McKinn said he was trying to arrange a Top Rank-sponsored boxing match for Morrison at Cliff Castle June 29.

"I'm a boxer," Morrison said.

Morrison returned to the boxing ring earlier this year in West Virginia, knocking out John Castle in the second round.

MMA star Dan "The Beast" Severn (81-15-7) will fight Victor Vincelette (2-2) in the main event Saturday night. Severn, who turns 50 next year, wrestled at Arizona State from 1976-80 and served as a coach there until 1986.