Lightweight remains deepest division in mixed martial arts

When Anderson Silva steps into the cage this summer with Chael Sonnen, the UFC middleweight champion will be facing the one man who's managed to give him a fight. Jon Jones takes on friend-turned-nemesis Rashad Evans next month, and if the light heavyweight belt holder passes that test, then what? The only thing that seems to be able to stop welterweight titlist Georges St-Pierre is a balky knee. Is there a featherweight out there who can hang with José Aldo? A bantamweight who can touch Dominick Cruz?

And then there is mixed martial arts' lightweight division, where the action is. Yes, there are a few heavyweights standing in line for a shot at UFC champion Junior dos Santos, but the 155-pound division is where the truly heavy traffic exists.

Benson Henderson is unquestionably king of the hill, having climbed over Frankie Edgar three weeks ago at UFC 143 to grab the UFC belt. And the ex-champ is second in command, as after several days of wrangling both behind the scenes and in the very public venue of social media, Edgar last week was assured of a rematch. But where does the pecking order go from there?

Unlike in other weight classes, several fighters outside the UFC figure prominently.

One is Eddie Alvarez, the former Bellator champion. Both he and the man who choked him out in November, Michael Chandler, are as elite as it gets in that fight promotion, but Alvarez has added appeal because he's near the end of his contract and could soon jump to the UFC. First, Eddie needs to erase the memory of the title loss, and he's going about it in a way that makes a lot of sense, even if it's unconventional within Bellator.

Rather than entering one of the fight promotion's signature tournaments held to determine a challenger for the 9-0 Chandler, Alvarez has opted instead to face Shinya Aoki at Bellator 66 on April 20 in Cleveland. Not that Alvarez (22-3) has anything to be ashamed about in the wake of his loss in a thrilling back-and-forth battle that might have been last year's best MMA fight, but stepping in with Aoki is a bold move aimed at instant name reclamation at a career crossroads.

Bellator boss Bjorn Rebney understands this, and he has a refreshingly compassionate take on the matter. "If he wins that fight, Ed's going to be in a terrific position to negotiate with us as well as the UFC," Rebney told MMAjunkie.com Radio the other day. "So as counterintuitive as it sounds for a CEO that actually writes the check to say it, I hope that's the position he's in, because the guy deserves it."

Makes you want to wish Bellator good luck in the negotiations, doesn't it?

But let's not get ahead of ourselves. Redemption doesn't come for free, and Aoki is no steppingstone. UFC-centric American fans might not know all that much about him, but the 30-5 Dream champion deserves to be part of the conversation when you're talking about the world's top lightweights. The Japanese submissions specialist -- 19 in his career -- was the last man prior to Chandler to beat Alvarez, finishing him with a heel hook in 2008, and he's won seven straight bouts.

The non-UFC fighter with the strongest footing on the lightweight ladder, however, is Gilbert Melendez. He's the guy who handed Aoki his most recent loss, via unanimous decision in 2010. That victory is part of the Strikeforce champion's six-fight winning streak, which has left him with few challenges within his promotion.

Melendez (20-2) is scheduled to defend his belt May 19, and next in line among Strikeforce fighters would likely be ex-champ Josh Thomson, who took a unanimous decision over K.J. Noons a couple of weekends ago. Thomson (19-4, one no-contest) and Melendez have a history, with "The Punk" winning their first meeting back in 2008 to grab away the title, and "El Niño" taking the rematch in 2009 to get the belt back. Since then, however, the oft-injured Thomson has lost momentum, and he didn't do himself any favors with a somnolent performance against Noons. Would a rubber match have much appeal?

Not to Cesar Gracie it wouldn't. Melendez' longtime manager and trainer has been lobbying for a new challenge for his fighter. "Gil is fighting May 19th," Gracie wrote on Twitter on Monday. "I hope Penn or Pettis." That would be B.J. or Anthony, "The Prodigy" or "Showtime." Interesting.

Calling out Penn (16-8-2) is a shrewd move by Gracie, who wants to put his fighter in with someone whose game -- and even more important, his name -- will elevate Melendez'. B.J. certainly has the name you'd love to see in the "W" column on your resume. And yet the former UFC champ is at a vulnerable stage in his career, having won only one of his last five bouts, that a 21-second flash knockout of past-his-prime Matt Hughes. Penn stated his intention to retire following his beatdown by Gracie fighter Nick Diaz back in October, and if he were to come back for this one last challenge, it would be against a fighter in his prime -- and with a head start in preparation, since Melendez was in camp with Diaz as Nick readied himself for the Penn fight.

A bout against Pettis (15-2), on the other hand, would have more risk and potentially more reward -- and not just for Melendez, either. "Showtime" might see a Strikeforce fight -- even for the title -- as a step down, after he was in the running for the first shot at Henderson's UFC strap. And for "El Niño," having Pettis as his opponent would bring less name recognition than if it were Penn. However, it would be a contest between men at the top of their games. Melendez has been indomitable in Strikeforce, and Pettis is coming off a nasty head-kick KO of Joe Lauzon earlier this month. It would be difficult to deny the winner of a Melendez-Pettis fight the next UFC title shot.

Then again, Melendez' training partner, Nate Diaz, and his May 5 opponent, Jim Miller, might have something to say about that. When they signed for a clash on the UFC on Fox card in East Rutherford, N.J., they were told that the winner would get the next title shot. UFC president Dana White reiterated that assurance as recently as last week, with the one caveat being that he first had to persuade Edgar to drop to the 145-pound division. Well, Frankie is staying put at 155, of course, and he'll be the one challenging Henderson, probably sometime this summer. So that leaves the Miller-Diaz survivor ... next in line?

With the lightweights, you never know. These guys simply don't stand still, which is what makes this weight class as exhilarating a place as there is in MMA.