Derek Hough Credit: Craig Sjodin/ABC via Getty Images

Dancing With the Stars: All-Stars is taking its toll on three-time champ Derek Hough.

The 27-year-old pro aggravated a pre-existing injury during the Oct. 30 broadcast. "I have a bulging disc on my vertebrae," Hough told Us Weekly while icing his neck. "I've had it for a couple years. I need surgery on it. It flares up and it did today unfortunately. It immobilizes me but we dance through it on adrenaline."

Adrenaline may not be enough. Pro dancer Mark Ballas, 26, will rehearse with Hough's celebrity partner, Olympian Shawn Johnson, as the blond star heals. "If all goes well, Derek will be better and cleared to dance next Monday with Shawn live on the show," Hough's rep told Us. "If not, Mark will step in, but hopefully that won't happen."

According to a source, "Derek is taking extra precaution because he doesn't want to aggravate his condition further. He trusts Mark and so he is putting Shawn in the most capable hands possible."

The source added that Hough "will supervise and do everything he possibly can" to ensure Johnson moves on in the competition. "It is likely he will dance with her live next Monday in the ballroom."

The night wasn't just about Hough, however, as Sabrina Bryan and Louis Van Amstel were eliminated. "The journey has been absolutely amazing, but to have to cut it short, that always sucks," Cheetah Girls star Bryan, 28, told Us. "Louis is incredible -- he really pushed me. To have someone so excited to teach you and dance with you is amazing. He was excited for what we were doing every step of the way and we both grew so much. I'm so incredibly grateful for this guy."

According to Van Amstel, 40, Bryan was the perfect partner. "She put it all on the line, everything. She did more than I expected. She took it to a different place. No one can take that away," the pro told Us. "It's almost indescribable."