Rycroft, 26, is a former Dallas Cowboys cheerleader and was a contestant on the dating reality show "The Bachelor."
"As you can see, Melissa is not with us tonight," Bergeron explained at the beginning of Monday's show. "She suffered an injury this week, complications following, which made her unable to dance tonight."
Usmagazine.com quoted Rycroft as saying she bruised a rib on last week's show.
"Unfortunately with a rib, there's nothing you can do about it, but we went in today, and I took it easy today, and I'll probably do the same tomorrow," she said.
Rycroft's dancing this week was judged on footage from rehearsal.