The banquet room at Wynn Las Vegas Resort broke out into laughter, but Penske later insisted he was serious.
“If he wants to do the double, I’d put him in it,” Penske said. “We’ve talked about it before. I guess I made it official tonight.”
Stewart was not immediately available for comment.
Penske-owned cars have won the Indianapolis 500 15 different times, but not since Helio Castroneves’ 2009 victory.
The Indy 500 is Stewart’s favorite race, but he has not entered it since 2001.
NASCAR’s three-time champion twice attempted to run both the Indy 500 and NASCAR’s Coca-Cola 600 on the same day: In 1999, he was ninth at Indy and fourth at Charlotte, and in 2001, he was sixth at Indy and third at Charlotte.
He hasn’t tried Indianapolis since, and has seemingly let go of his childhood dream of winning the 500. He has twice won the Brickyard 400, NASCAR’s race at storied Indy.
“The hard part for me was you make that decision when you sign up to do (NASCAR),” Stewart said last January. “The decision you make, you have to come to peace with yourself with saying `I’m not going to do this.’ That was my childhood dream anyway. It was hard knowing when I signed that (NASCAR) contract that I was writing off the opportunity to go race at Indy.
“It’s figuring out at the end of the day what do you really want to do. I guess that’s the part that even though it was hard to watch opening day of practice at Indianapolis, I’m enjoying what I’m doing, too, and this is what I want to do at the end of the day. It makes you want 30-hour days and 400-day years and we always want to do more than what we’re capable of doing, but the reality is you have to pick at some point and choose your career path. This is what I’ve done.”
Stewart ran the Indy 500 five times, winning the pole as a rookie in 1999 and leading 44 laps before his engine failed. His highest finish was fifth in 1997.
Penske said it would have to take some scheduling adjustments between IndyCar and NASCAR in order for Stewart to run the Indy 500 and the Coca-Cola 600 at Charlotte Motor Speedway, and he’s not sure the two series could work together to make it happen.