ESPN.com has learned from Mir's camp that a nagging knee injury forced him to miss two weeks in the middle of a 12-week training camp. The setback nearly forced him to pull out of the fight and ultimately prevented him from hitting his target weight of 252 pounds.
"The ligaments in his knee were damaged," said Jimmy Gifford, Mir's head trainer. "He missed weeks seven and eight of the camp. Because of the knee issue, the weight didn't come off like we thought it would. He won't be that heavy for his next fight, I can promise you that."
The former UFC champ has apparently settled on a comfortable weight after experimenting several options during the past two years. After suffering a second-round TKO loss to Brock Lesnar at UFC 100, where he weighed-in at 245 pounds, Mir exploded to the maximum 265 for his next fight. Following a loss to Shane Carwin in 2010, he strongly considered dropping to the light heavyweight division.
Instead, Mir remained a heavyweight and has now won back-to-back fights for the first time since 2008. His unanimous decision win over Nelson was initially criticized by some, including UFC president Dana White; however it appears that was due in large part to neither fighter being completely healthy.
Two days after the event, Nelson was diagnosed with walking pneumonia at an emergency room in Las Vegas. Around the same time, Mir revealed he had dealt with a bout of Bronchitis one week before the fight.
"The Sunday before the event, he ended up with Bronchitis," Gifford said. "His whole family was sick. The game plan in the fight was to go for it early, try and land some big shots and then pull off the gas pedal. We were worried about his breathing. Five days before the fight we had to stop practice because he had a panic attack and couldn't breathe. First time that's ever happened to him."
Gifford said Mir was discouraged at first when he heard White's criticism of the fight, but ultimately took it as a compliment the UFC's expectations on him are so high.
With no health issues to speak of coming out of the Nelson fight, Mir's camp says several future opponents are being discussed -- most of whom are already scheduled to fight -- and that he would like to compete again within the next six months.