In May, Busch easily passed an IndyCar rookie test by turning laps of over 218 mph in a vehicle provided by Andretti Autosport. That experience led the Las Vegas native to pursue a potential seat in next year’s Indianapolis 500, with an appearance at this month’s race at Auto Club Speedway as a tune-up.

His success in NASCAR this year has changed that plan. Busch has led the single-car No. 78 team into the Chase for the first time, an effort that helped him land a ride at Stewart-Haas Racing for next season.

"The Chase has gone off to a good start for us, but it hasn’t been the best. You have to be at a perfect level through the first five races, I think, to know how to position yourself for the last five in the Chase," Busch said. "So with all those thoughts, I’ve shelved the IndyCar thoughts. The reason I wanted to do Fontana this year is to get experience, and to do my homework and to be better prepared if I were going to run Indianapolis next year."

At the annual NASCAR event at the Brickyard earlier this year, Busch said a potential Indy 500 appearance next season was only a matter of sponsorship. Not running the Fontana race, he said, doesn’t necessarily preclude him from potentially still competing at Indianapolis in May of next season, although it would leave him at a disadvantage.

"The window closed for running Fontana this October. It’s not closing out the chance of going to Indianapolis, but I wanted to be better prepared — to have a better outing, to be more competitive if I was to show up at Indy next year," he said. "So now with that opportunity gone, next year there’s still a chance at running Indy, I just won’t be as prepared to race. It might just be more of a scenario where I’ve got to learn that much more in the month of May instead of being prepared for it."

Busch’s car owner next season, Tony Stewart, is a former IndyCar champion who knows all about running both the Indy 500 and NASCAR’s Coca-Cola 600 on the same day. To this point, though, Busch hasn’t had a chance to solicit his future teammate’s advice on potentially doing the double next year. Right now, the Chase takes precedence.

"I haven’t done much of my homework that I need to do," Busch said. "The preparation and the key pieces, we’re still trying to fit them all into the right place. When I know that’s going to come true, then we need to go and jump on it and prepare for our race, our exam, our big test, which would be Indianapolis."

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