'Dancing With the Stars': Partners Derek Hough and Shawn Johnson both injured

shawn-johnson-derek-hough-w4-dwts.jpg Shawn Johnson's knee sprain was a major storyline on "Dancing With the Stars: All-Stars" -- especially since a knee injury ended her gymnastics career.

What the show didn't reveal, however, is that her pro partner, Derek Hough, was also dancing through pain. While icing his neck backstage after Monday night's (Oct. 29) country-themed performance, the three-time champ revealed that he suffers from a bulging disc in his vertebrae, which flared up earlier that day.

"I've had it for a couple years," he told us, "but once it flares up -- like it did today -- it sort of immobilizes me."

"I saw him today turn his head and I was like, Uh-oh," added Shawn, who could immediately tell something was wrong. "I was like, What did you do? It slowly got worse."

"I danced through it," Hough said, holding a bag of ice under the back of his shirt collar. "A little adrenaline helps out, [but now I have] to figure out how to get through it."

He's not just talking about himself: his partner suffered a sprained knee, which Shawn told us is "unfortunately something I'll have to deal with for the rest of the season."

The pair are confident they can "push through it," and Shawn insists that her injury was "more emotionally overwhelming than physically painful or demanding."

"Reliving the whole knee pain took me back to the Olympics and retiring and everything I had to go through." (The gold medalist's knee injury ended her comeback before the 2012 London Games.) "The idea that that would take me out of ["Dancing With the Stars"] just devastated me."

For now, Shawn says, "my knee's doing OK."

Maybe judge Len Goodman picked the best time to complain about Hough's "frippery": In response, the ballroom pro said, "I'll do this for you, Len: I'll keep it simple."

"I'll go back to Season 6 choreography if that's what you want," he quipped.

Here's hoping the couple -- serious contenders for the disco-ball trophy since the judges called their quickstep in Week 3 the best dance in "DWTS" history -- aren't derailed by their injuries.

Fellow Season 15 dancer Melissa Rycroft suffered a herniated disc Oct. 22, but waltzed her way to a nearly perfect score (29.5/30) this week with partner Tony Dovolani.
Photo/Video credit: ABC