UFC featherweight champion Jose Aldo will not defend his title Jan. 1 in Las Vegas after suffering a compacted vertebrae in his neck, ESPN.com confirmed Tuesday.
Set to make his UFC debut after an impressive run as the WEC's 145-pound champion, Aldo, who was awarded the UFC belt Saturday prior to UFC 123 in Auburn Hills, Mich., experienced tingling in both arms while training in Brazil, said Aldo's representative Jorge Guimaraes.
"He's heartbroken," Guimaraes said of the 24-year-old mixed martial artist, whose 18-1 record lands him near the top of most pound-for-pound lists. "But he said he doesn't care about the injury and he'll fight."
Aldo's trainer, Andre "Dede" Pederneiras, said different. At the behest of Pederneiras, Aldo underwent an MRI after it was clear the fighter was operating at less than full strength in the gym.
"He's officially out," Pederneiras e-mailed.
Doctors recommended Aldo take a month off from training to focus on physical therapy.
The vertabrae is "compacting the spine, and they noticed he lost a lot of strength in the right arm," Guimaraes said.
Heavy.com first reported Aldo would not compete at UFC 125 against 22-year-old challenger Josh Grispi (14-1), which features a lightweight championship in the main event between titleholder Frankie Edgar and challenger Gray Maynard.
Josh Gross covers MMA for ESPN.com. Follow him on Twitter at JoshGrossESPN.