Former NASCAR driver Tony Stewart has parted ways with Donny Schatz, effective immediately, ending nearly an 18-year run in Sprint Car racing. Together, they captured eight World of Outlaws championships and nine Knoxville Nationals victories, along with 234 victories.Stewart cited underwhelming on-track performance as the reason for the split, despite major efforts to turn their season around—including a switch from Ford to Chevrolet engines. Ten-time World of Outlaws champion Schatz will be replaced by Kerry Madsen, who will take over the #15 car at Ogilvie Raceway this Friday (Aug 15).In a press release, here's what the three-time NASCAR Cup Series champion said (via Fully Injected Motorsports):“Donny has been an incredible part of TSR for nearly two decades, he’s helped build this organization into what it is today. 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.“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. Making a change now gives each of us the chance to reset and refocus before 2026.”Donny Schatz's last race with Tony Stewart Racing was at the Knoxville Nationals last week. He had a disappointing qualifying run but was able to claim the final spot in the Knoxville Nationals, extending his streak of consecutive Nationals A-mains to 27. He started the 50-lap race in 20th and later finished in 11th.His replacement driver, Kerry Madsen, is coming from the #55 VerMeer Madsen Racing team. He already had 37 starts in TSR's #14 sprint car and won six events in 2021.Tony Stewart's wife Leah shares how Dodge’s support fueled TSR’s riseOver in the NHRA (National Hot Rod Association), Tony Stewart has been having strong runs with Dodge—currently second in the Top Fuel standings. His wife, Leah Pruett, explained that the Michigan-based automaker's support has been instrumental in the team's success through the years.In an interview with Mamba Smith on the Dodge GarageCast (via YouTube), Leah Pruett said:“We had Dodge's backing [...] If it wasn't for them, we would have never been able to make that move.” [13:06]Leah Pruett, who originally drove the team’s Top Fuel entry, is taking this season off to look after their firstborn, Dominic James, who was born in November 2024. This is Tony Stewart’s second season in the class, following his debut season in 2024 when he won the Rookie of the Year award.