American drivers Graham Rahal and Josef Newgarden will start from the back of a 25-car field Saturday in the Grand Prix of Indianapolis after failing post-qualifying inspections.

The IndyCar Series made the announcement Friday night. In a news release issued about five hours after qualifying ended, the series said both cars failed to maintain the minimum car weight of 1,610 pounds on street and road courses.

Rahal, who drives for his father's team, qualified third and was the top Honda qualifier.

Newgarden, who drives for Ed Carpenter Racing, qualified fifth.

The penalties voided both qualifying times.

Rahal will start from the No. 24 spot and Newgarden will start in the 25th and final spot.