10/11/2011 at 09:10 PM EDT
Dancing with the Stars
has now had its biggest injury of the season.
Derek Hough dislocated his shoulder during rehearsals Tuesday but felt able to perform as scheduled with his sister, former Dancing
pro Julianne Hough
, in her return to the ballroom.
"He popped it back in, but he is still in a lot of pain," a source tells PEOPLE.
Hough is the partner of one of the top contenders, Ricki Lake. –Dahvi Shira