Chmerkovskiy, who exited the ABC show in week three with Entourage star Debi Mazar, has been training with Hough's celebrity partner Joanna Kruppa.
Hough is currently ill and it is not known whether he will be able to perform on this week's show.
"Think I'm getting the [flu]," he wrote on Twitter. "Serious sweats... My whole body is aching like crazy I can barely stand up... And I'm coughing like crazy."
After visiting a doctor, he added: "Had a temperature of 104... had an IV in my arm for 2 hrs... Maks is steppin' up for me helpin' Jo."
Last week, Aaron Carter claimed that the "energy" on the show's set had improved following Chmerkovskiy's exit.