But his score was not the lowest. NFL Hall of Famer Michael Irvin, who was told by judge Bruno Tonioli that he danced "like a truck," scored 14 for his samba.
Host Tom Bergeron created some tension by referring all evening to DeLay's injuries, but not saying whether he would pull out of the contest, as his doctors advised, or continue dancing.
"What's a little pain when you can party?" DeLay joked as he took to he floor in a red outfit with blue and white accents. His partner's costume featured white stars on a field of blue.
Billed as "Latin Night," the show featured some interesting moments and Paul Abdul, among other stars, in the audience.
Fighter Chuck Liddell's samba in a puffy-sleeved Latin costume was described by one judge as "the samba from Zombietown" and by another as thoroughly entertaining. His score was 17.
When Tonioli called entertainer Donny Osmond's rumba "a bit airy-fairy," the singer responded by leaping across the judge's desk and giving Tonioli a mock kiss.
"I don't think they're going to let me back in Utah any more," said Osmond, who is known for his clean-cut family-friendly performances. He got a grade of 21.
Singer Mya, who has been at the top of the leaderboard, earned the first 10s (two of them) of the season, for a top score of 27 for her rumba.
Olympic champion swimmer Natalie Coughlin, who also did a rumba, was just behind her with a score of 26.
"I knew you could fly but you've gone stratospheric tonight. Sexy beast," said Tonioli.
Carter, who tied with Mya for the top spot last week, fell short with a rumba that earned only 21 points.
Actress Kelly Osbourne who wowed judges with her Viennese waltz in the first show, then fell short last week, appears to be coming back up in the rankings. Her samba earned her a 20.
Also in the middle of the pack were model Joanna Krupa (23) snowboarder Louie Vito (20), "Iron Chef America" host Mark Dacascos (18) and actress Debbie Mazar (17).
Judge Len Goodman, who was off last week, gave out some high scores to the first few dancers, prompting Bergeron to speculate that he has mellowed. But before long, he was back scoring more severely than the other two judges.
Last night's scores will be added to audience voting to determine which dancer will go home after tonight's show. Already eliminated this season were dancer Macy Gray, actor Ashley Hamilton, and model and entrepreneur Kathy Ireland.