04/27/2009 at 12:00 AM EDT
the leader board last week with a sizzling Argentine tango, Melissa Rycroft
suffered an unexpected setback: She had to sit out of Monday's performance show due to an injury.
star suffered a rib injury and couldn't perform the jive with partner Tony Dovolani
. She also sat out of the group dance, the mambo.
Host Tom Bergeron
says Rycroft is talking with doctors, and the prognosis is a hairline fracture of one of her ribs.
Since Rycroft couldn't perform, the judges scored her by reviewing her rehearsal footage taped earlier Monday.
She's the second star this season to be scored on rehearsal footage. Earlier in the season, Steve-O
sat out a performance when he injured his back
, forcing the judges to score his rehearsal dance.