FILE - Marco Andretti, left, talks with Mario Andretti before IndyCar practice laps in Detroit, in this Friday, June 1, 2012, file photo. Marco Andretti made the decision at the start of this year to step away from full-time racing and essentially end three generations of the most famous family in motorsports competing at the highest level. (AP Photo/Dave Frechette, File)

FILE - Mario Andretti rides with his grandson, driver Marco Andretti, to the pits before practice for the IndyCar auto race on Belle Isle in Detroit, in this Friday, June 1, 2012, file photo. Marco Andretti made the decision at the start of this year to step away from full-time racing and essentially end three generations of the most famous family in motorsports competing at the highest level. (AP Photo/Carlos Osorio, File)