Tony Stewart said ''this has been one of the toughest tragedies I've ever had to deal with, both professionally and personally. It will affect me forever," in his opening remarks from Atlanta Motor Speedway.
He reached out to Kevin Ward Jr.'s family, calling each member by name and said ''I want them to know I'm thinking about them and praying for them."
Today's return to the No. 14 Chevrolet and the sport in which Stewart has won three Sprint Cup championships comes after he missed three consecutive races in NASCAR's premier series since he struck and killed Kevin Ward Jr. on Aug. 9 during a sprint car race at Canandaigua Motorsports Park in upstate New York.
NASCAR president Mike Helton will address reporters at 2 p.m.
There was no word from NASCAR or SHR on whether Stewart had requested a waiver to become eligible for the Chase for the Sprint Cup.
Ontario County (N.Y.) Sheriff Philip Povero said Aug. 12 the investigation into Ward's death would take at least two more weeks.
A spokeswoman for the sheriff's office told USA TODAY Sports on Friday morning just hours before the SHR news conference there was nothing new to report on the status of the investigation, which still is ongoing. She said they didn't expect to announce any news Friday.
Sponsor Mobil 1 has its logos on the No. 14 Chevrolet at Atlanta, a spokesman told USA TODAY Sports.
NASCAR executive vice president and chief racing development officer Steve O'Donnell said in a statement Thursday that Stewart: "has received all the necessary clearances required to return to all racing activities and therefore is eligible to compete this weekend at Atlanta Motor Speedway."
NASCAR's cutoff for the 10-race Chase is Sept. 6 at Richmond International Raceway. Stewart would need to win this weekend or next week at Richmond and get a waiver from NASCAR to be eligible (drivers must at least attempt to qualify each weekend).
NASCAR implemented a rule formalizing procedure for drivers who are involved in accidents or who are unable to make forward progress in their cars in the wake of the incident, in which Ward exited his race car and was walking down the dirt track under caution when Stewart's car hit him.
Drivers now are required to remain strapped in their cars -- unless they are in immediate danger from fire or another hazard -- until safety crews arrive and can escort them from the scene. No driver is allowed to walk onto the racing surface.
After SHR vice president of competition Greg Zipadelli said it would be ''business as usual'' at Watkins Glen International the day after the incident, the team quickly reversed course and said Stewart would sit out. Nationwide Series regular Regan Smith filled in for him there.
Stewart, who was described by police at the accident scene as being ''visibly shaken,''released a statement that Sunday that read:
"There aren't words to describe the sadness I feel about the accident that took the life of Kevin Ward Jr. It's a very emotional time for all involved, and it is the reason I've decided not to participate in today's race at Watkins Glen. My thoughts and prayers are with his family, friends and everyone affected by this tragedy."
Stewart has been in seclusion since the incident. SHR executive vice president Brett Frood said the driver was "grieving. ... It will be up to Tony when he's ready to get back in the car," when the team announced Jeff Burton as a fill-in before the race at Michigan International Speedway.
Burton was behind the wheel of the No. 14 Chevrolet at Michigan and last week at Bristol Motor Speedway, notching finishes of 37th and 15th, respectively.
If Stewart doesn't qualify for the playoffs, this will mark the second year in a row NASCAR will be missing one of its stars during the championship run. Stewart was sidelined for the final 15 races in 2013 after breaking his leg in a sprint car accident. He required three surgeries and months of rehabilitation to be able to get back in a Cup car for this year's Daytona 500 in February.