A boxer's last resort is his power, because the punch is the last thing that leaves him. Everything else goes first: speed, the ability to slip punches, timing. Reflexes wane, and with them the quick hits and combinations. Passing years alone steal from the kind of peak conditioning needed for relentless work during a fight. Mike Tyson showed little in his last fight, Jan. 16, against Francois Botha--except the power to flatten an almost stationary figure, which he did at 2 minutes 59 seconds of the fifth round.

Then he went to jail and now he's back. It's repetitious. It's sad. So what if he knocks out Orlin Norris Jr. Saturday night in Las Vegas in his first fight since being released from jail in Montgomery County May 24? Norris is the quintessential journeyman. He has boxing skills, but he long ago passed his prime. What if Tyson doesn't knock him out? What a quantum reversal that would be for the 33-year-old who, on Nov. 26, 1986, became the youngest heavyweight champion--because Norris, at 5 feet 10, is so much smaller than Botha that he gives Tyson the opportunity to take on someone his own size and look decent boxing.

"My timing and my speed are much better. I'm throwing sharper punches," Tyson told reporters this week, addressing his weaknesses against Botha--a lack of timing, speed and sharp punching.

One measure of Tyson's diminished status is that, after this latest layoff resulting from 3 1/4 months in jail for assaulting two motorists in a fender-bender, he's not capable of fighting an opponent who could be "sold" on pay-per-view television. That worked once, when Tyson met Peter McNeeley in 1995 after a four-year layoff because of his conviction in Indiana on rape charges, but no one can sell nothing for something twice. So the scheduled 10-rounder between Tyson and Norris, a 12-1 underdog, will be shown on Showtime, only the second of Tyson's 10 fights since 1990 that has not been on pay-per-view.

"Norris is a good opponent for Tyson at this time," said Ollie Dunlap, boxing manager and Sugar Ray Leonard's onetime aide-de-camp. "Botha is a cute fighter, better than given credit, because he throws sneaky little punches. Norris is methodical. He will try to fight Tyson, like Buster [Douglas] showed how to do it. You box him, but you know when to box him and when to fight him. A one-two combination makes Mike back up, and Mike's not a good fighter backing up. That's when you fight him. When he's coming at you, you box him, sidestep, use lateral movement. That's what [Evander] Holyfield did" in their first fight, when Holyfield stopped Tyson in 11 rounds.

"But, of course, Norris, being past his prime, isn't likely to be able to carry it out. I wouldn't think the fight would go more than seven rounds."

A measure of Tyson's lingering appeal is that he has been on the downside of his career this entire decade, if not longer. He turned pro in 1985 and peaked against Michael Spinks, June 27, 1988. He hasn't been the same since Douglas knocked him out in Tokyo in the 10th round, Feb. 11, 1990.

"Sometimes a good beating takes the fight out of you and dims your career," Dunlap said. "There are any number of examples. Like Ray against [Wilfred] Benitez. Most fighters have five prime years and Mike had his from 1985 until Douglas. Once in a while you get seven years, but not often."

Tyson speaks of coming "all the way back," of recapturing a title. Anything's possible in that there are so many titles, but his words really are as empty as Sugar Ray Robinson's when that legend was staying far, far too long and fighting in the mid-'60s in such places as the Washington Coliseum against the caliber of opponents who once merited a place in the same ring only on his undercards.

Tyson sparred three rounds Tuesday at the MGM Grand, the fight site, against Everett "Big Foot" Martin in what has been Tyson's only open workout while training for this fight. Tyson knocked down Martin in the first round with a wicked left hook to the chin, and also hurt Martin when a left hook landed on Martin's elbow. Martin's ring record is 20-29-1.

"I'm feeling really good," Tyson said afterward. "I feel my focus is much better than it was for Botha. I had to endure a lot before the Botha fight. I'm coming out of a much more serene setting for this fight. I feel totally different."

Tyson admitted ballooning to more than 280 pounds while in jail. He dismissed the effect of gaining and losing the extraordinary weight--but that's part of the erosion in his talent.

"People make a big deal of me having to lose all that weight, but I've always had to do that," he said. "I'm just blessed with the ability to lose weight quickly. If I don't work out, I'm going to gain weight. I've gone up and down my whole career. . . .

"I still feel I can conquer the world, but I know it takes a lot of hard work and sacrifice. Orlin Norris is a good fighter, but I don't care how well he has prepared. I'm preparing to knock him out cold."

The most shocking thing that Tyson has said recently came in an interview with the Los Angeles Times. Tyson said he would bite again if desperate enough. This week, he also dismissed those words.

"I was just talking smack, just hyping the fight," he said. "I was trying to sell some tickets. The Nevada State Athletic Commission knew I wasn't serious. They knew the trauma that I went through. I won't do that in the ring."

He did, however, try to break Botha's arm at the bell ending Round 1, admitting it after the fight.

Tyson's trainer, Tommy Brooks, envisioned a nightmare of an evening for Norris, a cruiserweight champion in 1993-95, who has a 50-5 record with 27 knockouts. He's the brother of Terry Norris, who gained passing fame by beating a washed-up Leonard. Tyson is 46-3 with 40 KOs.

"I don't know what kind of punishment Norris can absorb," Brooks said. "They asked for the thunder and that's what we're going to give them. That's what he wants to prove: I'm Mike Tyson and I'm the baddest man on the planet and I still have the power. Mike can go out and capture the crowd again. That's what he's looking to do. There's going to be no decision. The fight won't go four rounds, but if Mike does what we've been working on, it'll be a two-round fight. With what we've been working on, there's no escape."

Special correspondent Tim Graham contributed to this report from Las Vegas.