"This has been one of the toughest tragedies I've ever had to deal with, both professionally and personally. This is something that will definitely affect my life forever," said Stewart, who has missed the past three Sprint Cup races after Ward's death Aug. 9. "This is a sadness and a pain that I hope no one has to experience in their life. That being said, I know that the pain and the mourning that Kevin Ward's family and friends are experiencing is something that I can't possibly imagine."
Stewart read his prepared statement at Atlanta Motor Speedway, where he will get back behind the wheel of his No. 14 Chevrolet on Friday for the first time since Ward's death. Stewart, who didn't take any questions, has been in seclusion since the incident.
He says he took time out of respect for Ward's family -- and so he could cope with the tragedy. He said, "Being back in the car this week with my racing family will help me get through this difficult time."
NASCAR president Mike Helton, in a separate news conference later Friday, said Stewart has been granted a waiver and can still qualify for the Chase for the Sprint Cup Championship, "if he were to earn a spot in it."
Stewart-Haas Racing executive vice president Brett Frood said it was "100 percent" Stewart's decision to race.
"For Tony, it's all about the healing process, and that's why he's in the car," Frood said.
The 20-year-old Ward had climbed from his car after it spun while racing for position. The race at Canandaigua (N.Y.) Motorsports Park was under caution because Ward spun out. He then walked down onto the racing surface, waving his arms in an apparent attempt to confront Stewart. Authorities said the first car to pass Ward had to swerve to miss hitting him. The front of Stewart's car then appeared to clear Ward, but Ward was struck by the right rear tire and hurtled through the air. He died of blunt force trauma.
Ontario County Sheriff Philip Povero has said investigators did not have any evidence to support criminal intent, but added Thursday that the investigation is still ongoing. Stewart has not been charged.
Stewart named each member of Ward's family and said that "every day I'm thinking about them." Frood said Stewart sent the family flowers and a card for the funeral, but he has respected the family's privacy and time to grieve.
"He's very emotional. It's been a difficult two weeks," Frood said. "But Tony is ready to be in the race car. He wouldn't be here if he wasn't.
"It will be important for Tony to spend time with the [Ward] family, and I believe that will happen at an appropriate time."
The three-time Sprint Cup champion pulled out of the race at Watkins Glen on Aug. 10, then skipped races at Michigan and Bristol Motor Speedway.
Stewart needs to win one of the remaining two races before the Chase to qualify for NASCAR's newly modified playoff system.
Despite a rule stating that a driver must attempt to either qualify or race the car in every points-paying event to be eligible for the Chase, Helton said Stewart was granted a waiver based on "a very unique set of circumstances to Tony and our sport."
"As a league and our responsibility to try to make decisions that are correct and right, sometimes we evaluate circumstances that are given us, and then make those decisions as correctly as we can," Helton said. "After evaluating the circumstances around this occurrence, we've come to the conclusion that Tony would be eligible to participate, if he were to earn a spot in it."
"For me, I don't really care about the sport," Stewart-Haas Racing teammate Kevin Harvick told ESPN on Friday. "At this particular point, I'm in the more 'Care about Tony Stewart' phase and helping my friend get through a very tragic situation."
Added SHR teammate Danica Patrick: "I'm sure he hasn't even worked through it yet, but one step is to get back to something that feels normal again. I'm sure it's been a very difficult time -- and he said it's been the most difficult thing he's ever gone through. As a team, we're here for him, and we're glad to have him back."
Heartbroken but eager to heal, Stewart rejoined the race for the NASCAR Sprint Cup championship surrounded by those he considers a second family -- his team, his crew, his rivals. He signed autographs. He talked with his crew about the car's setup. He hugged Kurt Busch.
In qualifying later Friday, Stewart qualified 12th with a fast lap of 29.504. His teammate, Harvick, turned a fast lap of 29.118 seconds to take the pole.
The Oral-B USA 500 is Sunday at 7:30 p.m. ET on ESPN.
Information from the Associated Press was used in this report
Stewart: Tragedy Will Affect My Life Forever
An emotional Tony Stewart expressed sorrow in his first public statement since his car struck and killed fellow driver Kevin Ward Jr. during a sprint car race in New York.