The Associated Press

LAS VEGAS - When Roy Jones Jr. was young, he used to beat up bigger kids all the time. It was no big deal, though he eventually grew tired of doing it just for fun.

"I stopped, because one day I wanted to get paid for it," Jones said.

That day comes today when Jones finally takes the chance his critics said he wouldn't, fighting John Ruiz in an intriguing matchup of sizes and styles for the WBA heavyweight title.

It won't be as easy as it was in the old neighborhood. History indicates it is nearly impossible.

Of the 13 light heavyweight champions who challenged for the heavyweight title, only Michael Spinks was successful. And, unlike Jones, Spinks had the size of a heavyweight when he beat Larry Holmes in 1985.

To beat a strong fighter who outweighs him by 33 pounds, Jones will need all his considerable boxing skills and more. He'll have to fight Ruiz from outside and stay away from him as long as he can into the scheduled 12-round bout.

At some point, though, he's simply going to have to fight him.

"You're going to get tired. The guy is going to catch up with you, and you've got to deal with the guy," Jones said.

Oddsmakers think Jones will deal with it well; he's a 9-5 favorite.

"He'll find these guys punch real, real hard," IBF heavyweight champion Chris Byrd said. "John Ruiz is not known as a big puncher, but he'll be a huge puncher compared to Roy."

Jones, whose only loss in 48 fights came on a disputed disqualification, took the Ruiz fight only after being backed into a corner by a growing chorus of promoters, television executives and writers who complained he was wasting perhaps the best talent in boxing.

Jones previously was content to keep his light heavyweight title by fighting a collection of no-names for $5 million a pop.

"I've got nothing to lose," he said. "If you get beat, you get beat by a heavyweight. You may not get this chance but one time in your life. If I don't get this, when is my big fight going to come?"

Ruiz might have been asking the same thing when he was looking for big-name opponents after three fights with Evander Holyfield left him with a piece of the fractured title. Those fights proved Ruiz was rugged and tough but did nothing to bolster his claim that he is a legitimate heavyweight champion along the lines of Lennox Lewis.

"He has to clearly win a big fight against a top fighter for that to happen," Emanuel Steward, who trains Lewis, said of Ruiz.

Jones put on weight and still was just 193 pounds to 226 for Ruiz at Thursday's weigh-in. Whatever Jones' risk, Ruiz's is greater.

So desperate was Ruiz to fight a well-known opponent, he agreed to let Jones pocket a $10 million guarantee while he must hope the fight is bought by a lot of homes to make money. If the fight sells well, that could mean about $3 million for Ruiz, but there's a chance he could walk away with nothing.

The formula for Ruiz to win is simple: Cut off the ring, keep the pressure on Jones and hit him anywhere you can to try slowing him. In clinches, Ruiz will lean on Jones and use his body weight to tire him.

"He loves to run around the ring," Ruiz said of Jones. "I'll lean on him, throw the heavier punches. It will take its toll."

Win or lose, Jones probably won't fight a heavyweight again.

"I came here for a one-shot opportunity so people could see a big fight," he said. "I'm going to be right. Trust me."

Tale of the Tape

	Ruiz	Jones
Record	38-4-1	47-1
Knockouts	27	38
Age	31	34
Weight	226	193
Height	6-2	5-11
Reach	77 1/2	70
Chest (normal)	44	38 1/2
Chest (expanded)	46	40 1/2
Biceps	15 1/2	13
Forearm	13	11
Waist	35	28
Thigh	23 1/2	22
Calf	14 1/2	14
Neck	18	16
Wrist	7 1/2	7
Fist	12	10