Red Bull Racing says Mears will drive the No. 83 Toyota for Vickers, who is undergoing treatment for blood clots in his legs and near his lungs. Mears finished 22nd while subbing for Vickers last weekend at Dover.
NASCAR granted Red Bull's request to switch drivers for the race.
Red Bull said Tuesday that Vickers has responded well to treatment but has not issued a timetable for when the 26-year-old can return to racing.
Vickers and Red Bull Racing general manager Jay Frye will meet with the media on Friday.