Eager to put 'em up

LAS VEGAS -- All mutual respect between B.J. Penn and Nick Diaz went out the window in a matter of moments Friday as the two main event competitors for Saturday's UFC 137 had to be quickly separated by president Dana White at the end of a raucous pre-fight weigh-ins at the Mandalay Bay Events Center.

After both fighters, who have been nothing but pleasant with each other in the leadup to the restructured card, easily made weight, the two then squared off for the staredown. The taller Diaz, no stranger to impromptu melees with other fighters, moved his forehead down into that of Penn, who responded with a shove of his head, and then the boss intervened.

The former Strikeforce champion, who was booed roundly when he entered the arena for his first fight in the Octagon in five years, then stormed right off the stage without doing the traditional short interview -- hardly a surprise for the man who was bumped from the original headliner against Georges St-Pierre for failing to meet press obligations.

However, Diaz had been playing very nice with the media all week since he was promoted back to the main event after St-Pierre was injured last week, forcing the cancellation of his welterweight title bout against Carlos Condit.

That ended Friday.

Penn, who weighed in at 169 pounds (Diaz was 170 even) stayed to speak with Joe Rogan, but only had a few words.

“(Diaz) is a good opponent,” Penn said. “It’s time to fight.”

Everyone on the card made weight, except for Tyson Griffin, who was 149 -- he needed to be 146 for his featherweight bout against Bart Palaszewski, which will kick off the live preliminary fights on Sportsnet.

Watch the two live prelims, including Dennis Siver vs. Donald Cerrone, Saturday on Sportsnet at 5 p.m. PT / 8 p.m. ET.

Griffin already told White he won't be making weight, so the fight will be contested at a catchweight of 148 pounds and the UFC veteran will surrender 25 per cent of his purse.

Matt Mitrione was 255 pounds for his co-main event bout against Cheick Kongo (234), while Roy Nelson, who comically showed up wearing a fat suit under a hefty sweater, weighed in at 252 pounds for another heavyweight bout against Mirko Cro Cop, who was 235 pounds.

St-Pierre's teammate Francis Carmont of France, who fights out of Montreal's Tristar gym, was 185 pounds for his UFC debut, as was his opponent Chris Camozzi.

Top-ranked Japanese featherweight Hatsu Hioki, a former featherweight champion in Montreal's TKO Championship Fighting promotion, was 145 pounds for his Octagon debut. He takes on George Roop (also 145) to open the main card.

There was a wardrobe malfunction right off the bat as Clifford Starks, who is fighting on the first undercard bout against Dustin Jacoby, had his underwear come down a little lower than intended, drawing some reaction from the crowd.

Meanwhile, Ramsey Nijem got some whistles as he came in wearing a playboy collar.

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