Few would argue that Cain Velasquez is the most talented all-around heavyweight in UFC history. But, in large part due to injuries, he's missing a big enough body of work to not be called an all-time great.



After shoulder and knee surgeries, Velasquez is scheduled to step back into the cage for the first time in 20 months and defend his heavyweight title against Fabricio Werdum in Mexico City in the main event of UFC 188 on June 13. It's UFC's second attempt to headline Mexico City with Velasquez, and it's the second straight sellout at the 21,000-seat Arena Ciudad.



Velasquez's parents were born in Mexico, and for years he's been the company's biggest star in that country. But fighting in Mexico City presents a unique challenge. Velasquez's success and reputation has been built on being not just the best conditioned heavyweight perhaps ever in MMA history, but a man who Herschel Walker -- who himself has been around big athletes in football, track, MMA, martial arts and even bobsled racing -- called the best conditioned man of his size that he'd ever seen.



Unlike Werdum (19-5-1), who lived in Mexico City for months before both fights, Velasquez (13-1) gave himself two weeks to acclimate his body to the new surroundings. And he doesn't appear too worried about it, noting that whenever he's been to Mexico City for promotional appearances, he's trained there.



"Every time I go down there, I always go for a run," he said. "I've done some other training there, light sparring stuff. I haven't [had a problem]. I've run pretty hard. I know a fight is different. But I felt it hasn't been a bad transition. I'll run and I feel fine, but if I go up a flight of stairs, I'll feel it then. I'm going two weeks before the fight. I think two weeks is early enough."

Mexico City is 7,832 feet above sea level, even higher than elevated U.S. cities like Denver (5,280 feet) and Albuquerque (5,352 feet).

More than Werdum, the biggest questions surrounding Velasquez for this fight are those centered on ring rust after so much time off, as well as if (and when) the physical wear and tear of his various injuries will bring him down to the level of the rest of the pack.



"It wasn't one instance where my knee got hurt," Velasquez said about the period leading to the Nov. 15 fight that fell through. "The year-in and year-out of training, the knee was breaking down, and it gave out in that moment. There's one thing I knew I couldn't do, and that was go on the ground. And that was the one thing I needed to do in this fight. I was in a fight injured before, and not been able to do what I wanted to do. It wasn't fair to me and it wasn't fair to the fans."



Somewhat lost in all this is that Werdum comes into the bout as the interim champion, based on finishing Mark Hunt in Mexico City in the last fight Velasquez pulled out of. Werdum is the Spanish language voice of UFC broadcasts in Mexico. Against almost anyone else, Werdum would go into Arena Ciudad as a huge crowd favorite, as he was against Hunt.



Velasquez was there that night, as a coach and teammate of the Team Mexico fighters in a Mexico vs. Latin America season of The Ultimate Fighter. He coached that season against a team from other Latin American countries, headed up by Werdum. After the season ended, a number of the members of that team relocated to San Jose, and trained at Velasquez's home gym, the American Kickboxing Academy (AKA). That night at UFC 180, his Team Velasquez had a big night.



"It was definitely bittersweet," he said about the first show. "The good thing was all the guys from the TUF show from Team Mexico fought and won. It was a good experience as a coach and as a teammate and as a fan being able to coach them. The bitter part was the fight with Werdum and Mark Hunt. I wished I was out there fighting."



So with the time drawing near, the fighter who comes across more machine than man -- like an almost emotionless Vulcan type, yet who explodes like a Tasmanian devil once the cage door locks -- says that he's excited to finally achieve a dream of fighting south of the border.



"It sucks that I couldn't make the first one," he said. "I always, when asked about the place I wanted to fight, it was always Mexico City. I'm happy I'm getting the opportunity to fight there again."



On paper, Werdum presents perhaps Velasquez's most difficult stylistic threat. Velasquez's game is about wearing people out standing and keeping constant pressure, before taking them down and putting a hurting on them when he gets them there. But of all the heavyweights, Werdum is considered the most dangerous off his back, a reputation proven five years ago this month when he submitted the man at that time considered to be the greatest heavyweight in MMA history, Fedor Emelianenko, in Velasquez's hometown of San Jose.



"I find him dangerous, yeah, I feel like he's a complete fighter," said Velasquez. "He does everything. He punches, he kicks, he's really good on the ground, and he's always getting better. Every time we see him fight, we see a new and improved Werdum, a guy who has more skills. That's what makes him dangerous. In the last fight with Mark Hunt, he was losing on the ground and losing on his feet. But then he threw that knee and knocked Hunt out, so even if he's losing, he's still dangerous."



Still, Velasquez's trainer, Javier Mendez, is less cautious than he's been for any of Velasquez's fights since he won the title from Brock Lesnar in 2010.



"I'm very confident in this one," said Mendez. "He's gonna kill him. Werdum has no chance. Cain's gonna do what he wants to do with him. Junior dos Santos is still the biggest threat to Cain Velasquez. In all respect to the other guys, Cain and Junior are at another level. I'm stating facts. Come June 13, Werdum can prove us wrong. But I don't think he will."



Mendez feels that Dos Santos is still the biggest threat to the title. But because they've fought three times, with Velasquez dominating the second and third fights, another fight between them isn't likely to happen soon.



"Werdum's not going to be able to handle the intensity," Mendez said. "He's not going to be able to handle the cardio. His best chance is a knockout or a submission. He can't win a decision. Nobody can beat Cain in a decision. He's never lost a round except for the one fight (where Dos Santos knocked him out in the first round to take the title in 2011).



"Keep this in mind, Mark Hunt lost 23 kilos (51 pounds) in three weeks before the fight. What happened in the first round? What happened in the second round before Mark Hunt hit the wall? Thank God Mark Hunt had the balls to lose that weight so quickly and fight a guy who had prepared in the altitude. Hunt wasn't prepared to lose that weight in that time and be in shape for that altitude."



But he does give Werdum credit for being an improved fighter.



"What's improved greatly is his striking," he said. "He's well rounded. He may be the best guy at taking someone down without having any wrestling experience. He's great, but Cain and Dos Santos are at a different level."