Derek Hough may have to be sidelined for the rest of the season on ABC's Dancing With the Stars after sustaining multiple injuries.

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Hough sprained his ankle, broke a toe and had ligament damage after rehearsing on Monday. The fan favorite pro is awaiting tests to see when he will be able to continue in the competition, if at all.

As the partner of Nastia Liukin, she will not have to bow out of the competition if Hough is unable to continue. Instead, fellow dancer Sasha Farber is acting as her new partner for the time being.

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Mark Ballas spoke with E! News about the development and expressed his concern for his friend.

"It sucks. It's unfortunate," Ballas said. "Hopefully he's going to be OK. The MRI results will come in [today] probably and we'll know more, but we're just praying that everything's OK."

Hough has been very busy this season in particular, considering he is also performing as the male lead in the New York Spring Spectacular. He is flying back and forth between New York and Los Angeles every week.

Liukin and Hough have turned into frontrunners at this midway point in the season. Their dances have gradually improved in terms of both technical aspects and entertainment value.

Hopefully Hough and company will find out some answers soon.

"I was with him until all hours of the night...Derek's an optimist," Ballas said. "He's always up and he's always bringing the people around him up. His energy is always positive."

Dancing With the Stars airs Mondays at 8 p.m. ET/PT on ABC.

Watch Liukin and Hough's latest dance here:

Tags: Dancing with the Stars Reality TV ABC