Anderson Silva hasn't been in the UFC octagon since his leg was shattered 13 months ago.

His opponent Saturday night has been away even longer, but not due to injury. Nick Diaz was just waiting for a fight worth his pain.

The enigmatic Diaz returns from a 22-month layoff to take on arguably the world's most accomplished mixed martial artist in the main event of UFC 183 in Las Vegas.

Silva's comeback from a devastating injury is the main attraction of the show at the MGM Grand Garden, but Diaz has been a dominant, divisive figure in the sport virtually since he was a teenager fighting his way out of a rough upbringing in Stockton, California.

Many MMA fans love the attitude and toughness that make him a compelling attraction opposite Silva (33-6) — and Diaz (27-9-1) agreed to end his semi-retirement for this big-money fight.

"They're going to use me to fight the most important guy, because any guys that you've got out there right now aren't really shining too hard," Diaz said. "So they'll use me any time they need a guy for a big fight. They need a real fighter that fights the way that they want, then all they've got to do is make a deal with me."

Diaz is moving up in weight to challenge Silva, who was on top of the sport until losing two fights to Chris Weidman in 2013. Although his leg appears to be sound, the MMA world will be holding its collective breath when Silva unleashes his first kicks at Diaz.

"I fight the same," Silva said. "My techniques, my style — I don't change nothing. I am training more. I think now I'm stronger. I'm faster and more experienced, but I don't change nothing. I go kick. I go boxing. Not too much, because Nick has the best boxing, but I go fight."

While the sport waits to see how Silva will respond, Diaz's return from consecutive losses is another compelling aspect of the UFC's traditional Super Bowl weekend show in its hometown.

Welterweight contender Tyron Woodley also meets up-and-coming contender Kelvin Gastelum, and crowd-pleasing lightweights Joe Lauzon and Al Iaquinta square off. Former women's bantamweight title contenders Miesha Tate and Sara McMann meet on the undercard.

Silva's return is an important development for the UFC, which has bounced back from a rough 2014 with a solid slate of January fights. The UFC lost key pay-per-view stars Brock Lesnar and Georges St. Pierre in recent years, but the 39-year-old Silva is thinking less about his marketing value and more about revitalizing his career, which he insists has no end in sight.

"It's my legacy," Silva said. "It's my dream, and the new Anderson is back. So more experience, more technique. I'm faster, stronger and happier, and the UFC is giving me one more chance."

Silva is one of the few fighters who attract more attention than Diaz, the bird-flipping triathlete, marijuana enthusiast and willing brawler who once held the Strikeforce and WEC welterweight titles.

Diaz has been uniformly respectful to Silva during the promotion — although he stayed in classic Diaz form by missing a flight to an open workout for fans this week.

Perhaps Diaz is in a good mood because he can eat. After more than a decade of draining weight cuts to 170 pounds for his welterweight fights, Diaz is thriving in training as a middleweight.

"I've been moving up in weight, so of course I'm going to feel a little stronger and more energetic," Diaz said. "When I fight at 170, especially if I fight three times a year, I'm never really 100 percent in any of those fights, because it's so hard to (make) 170 pounds. It's hard to do that three times in a year, and then I've never had a year off."

Diaz is healthy and rested after his lengthy octagon absence, yet he again demonstrated his disarming candidness earlier in the promotion for this bout when he acknowledged he doesn't have much fun in his sport.

With an enormous fight just a few days away, his opinion hasn't changed.

"That's how it is," Diaz said. "I enjoy a lot about it, a lot about mixed martial arts and jiu-jitsu and training with friends and people, but fighting is hard work. It's a hard job."