Jordan has missed two days of training and fellow pro Ian Waite has stepped in to help Van Outen.
The pro damaged his ankle before last Saturday's waltz routine, but he carried on regardless and the pair topped the judges' leaderboard.
Writing on Twitter about his injury, Jordan said: "Can't walk right now! Oops.. Fell down a step onto my ankle. Then had to dance with Denise and do the pro dance."
He added later: "GOOD NEWS!!! Nothing broken....but I've been told it doesn't look good. But I know I'll be fine soon..!
"7 years on Strictly I've never missed a show or training through injury! This year my eye, nose and now ankle! I blame you @denise_vanouten."
Strictly Come Dancing show 6 - in pictures:
Copyright: BBCVan Outen appeared unconcerned by Jordan's latest knock, joking that she'd be happy to get a new pro.
"I'm praying I get to dance with someone else next week," she wrote. "Be nice to have a break from you."
Judge Craig Revel Horwood said on last night's It Takes Two that he would happily step in for Jordan this weekend.
"I don't think [his ankle's] good. He was really limping after the show on Saturday night, so I was slightly concerned," Horwood told Zoe Ball. "I might have to fill in, darling!"