The IndyCar Series driver was scheduled to begin filming the NBC hit show immediately after the Oct. 16 season finale race at Las Vegas Motor Speedway. The race was cancelled following an early 15-car accident that killed Wheldon, and Andretti decided he could not honour his commitment to do the show.
"I had a private plane right next to the track in Las Vegas, and we were literally going to start filming hours after that race," Andretti said this week during testing for the March 25 season-opening race at St. Petersburg.
"I lost my maternal grandfather the same week and I was just like 'I'm not ready to do this.' I always said if my heart is not in it 100 per cent, then I'm not going to do it. I knew I was not going to be at my full potential. I was not going to do well. My mind wasn't in it."
Wheldon, a two-time Indianapolis 500 winner, had agreed the morning of the race to rejoin Andretti Autosport for the 2012 season, and would have been one of Andretti's teammates.
Michael Andretti ultimately replaced his son on the show, and joined the cast midway through the first episode. He's made it through the first three boardrooms heading into Sunday night's telecast.
"I am glad Dad stepped up because it's great for all of us, but I didn't want to be seen on national TV in the state I was in," Andretti said.
Michael Andretti has not been featured through the first three episodes, and the Internet has been abuzz about how little he speaks on the show. Marco Andretti wouldn't bite when asked about his father's seemingly small role.
"He's still there, so, I don't think he's doing too bad," he said. "They can choose to have you perceived anyway they want, I guess, and that's the tough part about it."