Alfonso Ribeiro Alfonso Ribeiro

The Carlton Dance might cost Alfonso Ribeiro the Mirrorball!

The Dancing with the Stars frontrunner injured his back in rehearsals Wednesday and might not be able to perform on Monday's semifinals.

"We can confirm Alfonso was injured during rehearsal," Ribeiro's rep said in a statement to TVGuide.com. "He is currently under medical evaluation. It has not been determined whether or not he will be able to perform on Monday." 

Dancing's Alfonso Ribeiro talks grueling groin injury

According to TMZ, which first reported the news, Ribeiro hurt his back overcompensating for the groin injury he suffered while doing his signature Carlton Dance last month. The back injury is apparently so bad he's having trouble walking and skipped rehearsal Thursday to get an MRI, according to TMZ. Sources tell TVGuide.com that Ribeiro is currently watching his partner Witney Carson rehearse their routines with a stand-in. 

In an interview with TVGuide.com earlier this week, Ribeiro said he didn't expect his body to "break down as early as it did," but that he was determined to make the finals.

"There's three weeks left. There's three shows left.  I've got two and a half weeks of dealing with this pain, and thenI will absolutely have time to let this thing rest and recover," Ribeiro said, referring to his groin injury. "It'll be really nice once that happens, but hopefully I can stay on the show all the way to the end and make it to the final, and deliver a hopefully amazing performance on the finale."

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