Canandaigua, NY ( - NASCAR driver Tony Stewart struck and killed a fellow competitor who was walking on the dirt track during a caution in a sprint car race on Saturday night at Canandaigua Motorsports Park.

The Ontario County (N.Y.) Sheriff's Department confirmed on Sunday morning that the driver struck was transported to F.F. Thompson Hospital where he was pronounced deceased at 11:15 p.m. ET (Saturday). Track officials have identified the driver as 20-year-old Kevin Ward Jr. of Port Leyden, N.Y.

Stewart, a three-time champion in NASCAR's premier series, will not compete in Sunday's Sprint Cup race at Watkins Glen International, which is roughly 50 miles southwest of Canandaigua. Stewart-Haas Racing announced that Regan Smith, a Nationwide Series regular, will substitute for Stewart in the No. 14 Chevrolet. Stewart had qualified 13th for this 90-lap event at Watkins Glen on Saturday. He is a record five-time race winner at this 2.45-mile, 7-turn road course.

"This is an unbelievable tragedy, and our hearts go out to Kevin and his family," Stewart-Haas Racing vice president of competition Greg Zipadelli said during a press conference on Sunday at Watkins Glen. "This is a very tough and emotional time for everybody - his family and our family at Stewart-Haas and Tony Stewart.

"With that being said, we feel that as a group Tony will not drive today. Regan Smith is on his way up. NASCAR has approved for him to get in the race car today. They are going to do everything they can to help us expedite getting his seat to be comfortable for him."

According to a release from the sheriff's department, the incident occurred at the exit of turn 2 just past the halfway point in the 25-lap Lucas Oil Super Sprint Feature race. Stewart and Ward made contact while battling for position, with Ward spinning out and hitting the wall. The race went under caution.

A video of the incident showed Ward climbing out of his car and then walking down the dirt track. He was pointing his finger in the direction of Stewart and apparently yelling at him to express his displeasure.

Stewart's car and the vehicle of another competitor traveling in tandem approached Ward. The first car swerved to avoid hitting him, but Stewart's vehicle struck Ward and dragged him briefly on the track before he came to rest. Track medical staff immediately attended to him before he was transported to the hospital.

The remainder of the race was canceled.

Early Sunday morning, Canandaigua Motorsports Park posted a message on its Facebook page, stating it "will not have an official statement on the accident that happened in the ESS race until tomorrow. Please pray for the entire racing community of fans, drivers, and families."

The sheriff's department said Stewart has cooperated with the investigation, which is ongoing. Sheriff Philip Povero noted during a press conference that Stewart "was visibly shaken by this incident and has promised his continuing cooperation in this investigation."

No charges were pending against Stewart at this time.

Zipadelli said he spoke with Stewart shortly after the fatal accident happened. When the two met at Watkins Glen in the morning, Stewart had made the decision that he would not compete in the Sprint Cup race.

"We talked last night, and then going through the night and giving Tony some time to sleep on it, I met with him this morning, and he feels strongly this is the right thing to do," Zipadelli said. "We at SHR support it and agree with it. It's a difficult time for all parties. There's not a lot you can do. The only thing we can do is do what we feel is right. And this is what we feel is right. We're supporting Tony on it."

The incident at Canandaigua comes one year after Stewart broke his right tibia and fibula during a wreck in a sprint car race in Iowa. Having three surgeries to repair his leg injury, he was sidelined for the final 15 Sprint Cup races of the 2013 season.

Last month in Michigan, Stewart raced in a sprint car event for the first time since his injury.

When Stewart competed in an event at Canandaigua in July 2013, he caused a crash that involved 15 drivers. One of the competitors caught up in the wreck, Alysha Ruggles, who was 19 years old at the time, suffered a compression fracture in her back.

According to Ward's website,, he began competing in Go Kart racing at the age of four in 1998. Ward finished second in his first race and went on to claim six track championships and roughly 250 feature wins in only eight years of Go Kart competition.

Ward had been racing in the 360 Sprint Car division since 2010. He won his first career sprint car feature in June 2011. This year, Ward was in his fifth season with the Empire Super Sprints.