One of the most successful pairings Sprint Car racing has ever seen is no more. Donny Schatz and Tony Stewart Racing have parted ways, effective immediately, the Brownsburg, Ind., team announced Tuesday, marking the end of an 18-year tenure that produced eight titles on the World of Outlaws Sprint Car Series and nine victories at the Knoxville Nationals.

• Q&A With Tony Stewart Following Donny Schatz's Release

Schatz of West Fargo, N.D., who just turned 48 years old on Sunday has not announced his next endeavor, but the TSR team has revealed its hired Kerry Madsen as the driver of the team's No. 15 through the end of the 2025 season.

In a statement issued by Inside Line Promotions, team owner Tony Stewart said "the achievements we’ve accomplished together are something that I’ll always be proud of, but in the past few years we’ve weathered changes in the sport and our performance hasn’t been to the level that both Donny and I expect.

"We’re both competitors to our core and we both hold ourselves to a high standard of performance that we’ve struggled to obtain," Stewart added. "Making a change now gives each of us the chance to reset and refocus before 2026," said Stewart, while also giving thanks to Schatz's incredible success since the two paired up in 2008.

Schatz racked up 234 World of Outlaws wins over an 18-year span, but had been winless this year.

“Donny has been an incredible part of TSR for nearly two decades, he’s helped build this organization into what it is today,” Stewart said. “We’ve had a driver-team owner relationship that has gone beyond that partnership, he’s become part of my extended family through the years, and I have the utmost respect for him and what his career represents — a generational driving talent."

Schatz's 11th-place finish in Saturday's Knoxville Nationals from the 20th-starting spot marks his final race with TSR. Schatz gained 17 positions between Friday's Hard Knox Night (15th-to-fifth) and Saturday's B-main (11th-to-fourth) just to qualify for his 27th straight Knoxville Nationals A-main, a streak that spans back to 1998.

Madsen's first his first race in the TSR No. 15 coming this Friday at Ogilvie (Minn.) Raceway on the WoO tour. Madsen drove for the TSR team in 2021, winning six times in 37 starts. Because Madsen is finishing out racing for points at Knoxville Raceway for Vermeer Motorsports, and Knoxville's finale is Aug. 23, TSR will have an interim driver for the World of Outlaw events Aug. 22-23 in North Dakota, announced at a later date.

“Kerry’s been in our car before and is a proven winner, so bringing him back feels natural. He knows our team, we know his capabilities, and I’m confident he’ll give us everything he’s got as we close out the season," Stewart said.