When DeMarcus Corley steps into the ring tonight against Floyd Mayweather Jr. at Boardwalk Hall in Atlantic City, he will find himself at a significant crossroads.

It has been nearly 10 months since the D.C. native's last fight -- a loss to Zab Judah that cost Corley his 140-pound WBO title. The loss not only dropped Corley to 28-2-1, it also raised doubts about his viability as a contender in a deep and talented division.

Whether he can regain his claim as worthy titleholder or be relegated to "opponent" status will be determined when he meets Mayweather in what the WBC is calling an elimination bout, with the winner earning a shot at champ Arturo Gatti.

It's a tall order for Corley. In Mayweather (31-0), who will be making his debut as a 140-pounder after winning titles at 130 and 135 pounds, he faces a man frequently mentioned in those "best pound-for-pound" arguments. And with Roy Jones losing last week, Mayweather's name is one of the first mentioned in such debates. (HBO, which is televising the fight, will show a replay of Antonio Tarver's knockout of Jones after Corley-Mayweather.)

"I feel like this is a title fight already," Corley, 29, said from his Atlantic City hotel this week. "It's not an elimination bout."

The pre-fight hype this week has been all about Mayweather. Corley, to many, simply is the opponent. It is a role he clearly does not want to take on full time.

Corley has hired a new trainer, Don Turner, to prepare. He has spent the last seven weeks with Turner in Arapahoe, N.C.

"Training was great, perfect," Corley said. "I'm in the best shape of my life right now."

Even before Mayweather's decision to move up to 140, the division was loaded with potential headliners -- Judah, Washington's Sharmba Mitchell, Gatti, Kostya Tszyu and even Britain's Ricky Hatton. Corley, meantime, is far from a household name, and the left-hander boasts neither an exciting fighting style nor a victory over a marquee opponent. Even when Corley held a belt, it was the lightly regarded WBO's.

Judah provided Corley his first high-profile opponent, but Corley was knocked down in the third round and eventually lost a damaging split decision -- albeit one Corley contests. Tonight's bout provides the same opportunity -- when asked what attracted him to the fight, Corley said, "The big name, number one . . . Me beating Floyd would put me back on top."

It won't be easy. Mayweather is a veteran of 13 title fights and has the confidence that comes with such experience. At a press conference in New York on Wednesday, he wore a black, long-sleeved pullover with "P4P" stitched above the left breast -- Pound for Pound.

"I told everyone six years ago I was the best," Mayweather said. "And, obviously, now I am the best."

Though his record is unblemished, his superlative boxing skills undeniable and his willingness to fight the best in each division he enters unquestioned, Mayweather, 27, still feels somewhat unappreciated. An emphatic victory tonight, combined with Tarver's left to Jones's jaw, could change that.

The lone, lingering question, however, is how Mayweather will deal with a true 140-pounder. Though five pounds does not seem like much, the difference between the ropes is huge. And Corley hopes to use it, and his left-handed style, to his advantage.

"His credibility is great at 130 and 135, he's beaten everybody there," Corley said of Mayweather. "But he hasn't fought a junior welterweight. And it will be much harder for him to adapt also because I'm a southpaw, and he's never fought a southpaw. . . . I don't think he'll be able to sustain not only the punches, but the pressure I'll be putting on him."

Tonight's fight will be just the fourth for Corley since he won the vacant WBO title on June 30, 2001. He is keenly aware of the layoff.

"It's not going to effect me," Corley said. "I've been in two training camps since my last fight. I trained with Ricardo Mayorga, when he was getting ready for Cory Spinks [in November], and I was in camp with Kostya Tszyu [in December and January] when he was getting ready for Sharmba Mitchell."