​Corey Day’s rapid climb through NASCAR isn’t slowing down.Hendrick Motorsports announced Wednesday that it has signed Day to a long-term contract extension, keeping one of the sport’s most closely watched young drivers in the organization for years to come. And Hendrick isn’t simply bringing him back for another season in NASCAR’s O’Reilly Auto Parts Series.Day is officially headed to the Cup Series.The 20-year-old will return to Hendrick’s No. 17 Chevrolet for a second full O’Reilly Series season in 2027 while also making his Cup debut with a limited schedule. Hendrick has not yet announced which Cup races Day will run or provided additional details about that program.It’s another major step for a driver who was still learning how to race stock cars on pavement just two years ago.Hendrick Motorsports Is Betting Big on Corey DayDay arrived at Hendrick Motorsports in December 2024 with an enormous reputation in dirt racing and almost none of the pavement experience typically associated with a driver on the doorstep of NASCAR.His learning curve hasn’t lasted long.Day has already won twice during his first full O’Reilly Series season, breaking through at Talladega Superspeedway on April 25 before winning again at Dover Motor Speedway on May 16. He opened the 2026 Chase with a runner-up finish at Darlington and left the weekend fifth in the championship standings.All of that has come before Day has even reached 70 career pavement starts in full-bodied cars.Hendrick has clearly seen enough.“What Corey has accomplished in such a short time is remarkable,” team owner Rick Hendrick said. “He came to us with generational talent but almost no experience racing on pavement. The fact that he’s already competing for a championship at this level is extraordinary, and he’s just beginning to scratch the surface.”That last part might be the most telling.Hendrick isn’t treating Day as a prospect it still needs to figure out. By signing him long term and already committing Cup races to him in 2027, the organization has laid out the next stage of his development before his rookie O’Reilly Series season is even finished.Corey Day’s NASCAR Cup Series Debut Is Coming in 2027There are still some important pieces Hendrick isn’t ready to reveal.The team hasn’t announced Day’s Cup car, the number of races he’ll enter or where his debut will come. What is settled is that he’ll get his first taste of NASCAR’s highest level while continuing to chase an O’Reilly Series championship full time.Jeff Gordon sees those Cup starts as the logical next test.“There’s no substitute for seat time, which makes Corey’s progress even more impressive,” the Hendrick Motorsports vice chairman said. “We see growth every weekend when he gets in the car. He puts in the work and isn’t afraid to ask questions and apply what he learns.”Gordon added that the Cup races will give Day “another opportunity to gain valuable experience a