Anthony Pettis can't catch a break.



Pettis' coach Duke Roufus told MMAFighting.com on Friday that Pettis "popped his knee" while training in Brazil this week. Pettis was in Brazil to promote his UFC 163 title fight against Jose Aldo.



When he flew back to Milwaukee, Pettis was still complaining about the knee, so he went to get MRI. That confirmed his worst fears: Torn meniscus. Four-to-six weeks of rehab needed.



As a result, Dana White announced on Friday that Aldo will now defend his title against Chan Sung Jung on Aug. 3.



The good news for Pettis is he will not require surgery, however, Roufus said another one of his fighters, Erik Koch, suffered a similar knee injury last year and he needed more than four-to-six weeks to get healthy.



"He's very distraught," Roufus said. "Anthony is a very resilient man. He just wants to regroup right now. What can you do? You can dwell on the negative or figure out a way to past this and get better."



Roufus said Pettis "begged" White to keep him on the card. He tried to convince his coach that he only needed three serious weeks to train for the fight, but the UFC didn't want to take that risk, for Pettis' sake.



"[The UFC] said, 'No, you got to be healthy,'" Roufus said. "I'm glad they're looking out for his best interests, too."



Pettis wrote on Twitter, "Injuries are part of the sport. Small tear in my meniscus. I was so ready for this fight, this won't stop me! Be back soon."



Unfortunately for Pettis, this scenario is all too familiar. He was promised a title shot after beating Benson Henderson in the final WEC fight in 2010 but then saw that opportunity slip away when then-champion Frankie Edgar and Gray Maynard fought to a draw, and Pettis lost to Clay Guida while waiting for Edgar and Maynard to finish their trilogy. He then thought he was going to get a title shot after knocking out Joe Lauzon in spectacular fashion at UFC 144, but that didn't happen either.



So after Pettis defeated Donald Cerrone in January, he took what he thought was a sure bet: a title fight at 145 pounds against Aldo.



Turns out, it wasn't a sure bet after all.



When asked whether this means Pettis will return to lightweight, Roufus said, "it's all in Dana's hands and the UFC," but Roufus explained that the drop to featherweight was always more about the challenge of fighting Aldo than finding a new home at 145 pounds.



"I don't think he wanted to be a permanent featherweight," Roufus said. "He wanted to fight Aldo but lightweight is his division. I'm not sure what's going to happen."



Coincidentally, Henderson's next title defense is taking place in Pettis' hometown of Milwaukee on Aug. 31 against T.J. Grant, and Roufus, while saying he thinks Grant deserves a title shot, is holding out hope he'll see the Pettis vs. Henderson in the near future.



"The fight I want, always, is the fight with Benson Henderson."