The UFC's new featherweight champion will have to wait a little bit longer to make his first defense of the belt.

The WEC's final 145-pound champ, Jose Aldo (18-1 MMA, 8-0 WEC), who officially was awarded his new UFC title prior to this past Saturday's UFC 123 event, has suffered an undisclosed injury in training and has been forced to withdraw from a scheduled bout with top contender Josh Grispi (14-1 MMA, 4-0 WEC) .

The two had been expected to meet in the co-main event of "UFC 125: Resolution," which takes place Jan. 1 at the MGM Grand Garden Arena in Las Vegas.

MMAjunkie.com (www.mmajunkie.com) today verified Aldo's withdrawal, which was first reported by Heavy.com.

According to ESPN.com's Josh Gross, who posted the news on his official Twitter account, the injury was a "compacted vertebrae (which) caused tingling in both arms" and will force Aldo out of action for "at least a month for therapy."

Currently, officials have not decided how to plug the hole on the card or if Grispi will get a new opponent, sources told MMAjunkie.com.

Aldo, who was installed as a UFC champion following the recent decision to merge the world's largest MMA promotion with its sister company, the WEC, formally was awarded the UFC's first-ever featherweight title this past weekend.

Aldo debuted for the WEC in June 2008 with a second-round TKO win over Shooto legend Alexandre Franca "Pequeno" Nogueira.

Following five consecutive knockout wins to open his WEC run – including three in the first round – Aldo was granted a title shot against then-champion Mike Brown. Aldo halted Brown with strikes in the second round.

Aldo then defended his belt twice with wins over Manny Gamburyan and Urijah Faber and is currently considered among the top pound-for-pound fighters in the world.