The pair was practising a routine for Monday night's (19May14) show when Ballas fell and popped his shoulder out of place during a complicated lift.
A spokesperson tells People.com, "Mark was seriously injured during camera blocking. His shoulder popped out during a lift and he was taken by ambulance to the hospital where he was treated and released. It's unclear whether or not he'll be able to perform on Monday's show."
Reports suggest Ballas has been advised not to perform on the live episode, but insists he wants to take to the floor.
He reached out to fans on Sunday (18May14) on Twitter.com, writing, "Hey y'all. I'm doing alright, thanks for the love."
One of the final four stars - Cameron-Bure, James Maslow, Meryl Davis, and Amy Purdy - will be eliminated on Monday, ahead of Tuesday night's (20May14) finale.