Melissa Rycroft was the top scorer on "Dancing With the Stars" last week, but she was absent from Monday's show.
Host Tom Bergeron says Rycroft sustained a painful rib injury that prevented her from performing. Her professional partner, Tony Dovolani, said she also suffered complications from treatment for the injury.
The couple was judged on a rehearsal performance and earned 21 out of 30 points for their jive. Former contestant Steve-O was also judged on a rehearsal performance when he hurt himself early in this season's competition.
Doctors told Rycroft she has a hairline fracture but can continue competing on the ABC dance-off.
Two prospective contestants- the singer Jewel and TV commentator Nancy O'Dell - were prevented by rehearsal injuries from competing and were replaced in the cast by Rycroft and Playboy cover model Holly Madison. Madison was eliminated from competition earlier this season.