The team called a news conference for Monday afternoon at its shop in Huntersville, N.C., and all signs seemed to point to newcomer Joey Logano taking over Stewart's Toyota.
Team president J.D. Gibbs declined to confirm the speculation Saturday night.
"We'll have an announcement Monday," he said.
Stewart, a two-time series champion, announced earlier this summer that he's leaving JGR after this season to become co-owner of a Sprint Cup Series team now known as Haas-CNC.
Gibbs said it would not be unusual for a team to hire a driver before he's ever run in NASCAR's premier series, noting that Stewart's first race was as a fulltime driver for Gibbs.
"We obviously think he's a very talented driver," he said of Logano.
Logano has run a limited schedule for JGR in the Nationwide Series since he turned 18 earlier in the year, and is expected to make his Sprint Cup Series debut in September at Richmond, the final event before the 12-driver, 10-race Chase for the championship opens.
That run, and any others in the premier series Logano makes this year, are expected to come for Hall of Fame Racing, an affiliate of JGR
Stewart and Logano were linked in a bad way earlier this week when both teams were issued harsh penalties by NASCAR for rules violations discovered after last week's Nationwide Series race at Michigan. NASCAR suspended seven JGR crew members indefinitely for attempting to manipulate a horsepower test and docked Stewart and Logano 150 drivers points each.
The teams were also docked 150 points each and placed on probation for the rest of the year after inspectors found magnets on the gas pedals of both cars after the race.
Titans sign RT Stewart to multiyear extension
Death of brother causes Gardenhire to miss series
NASCAR delays Gibbs penalties another day
Gibbs Racing says so long to Stewart
