Larson was not allowed to make a qualifying attempt Saturday at Talladega (Ala.) Superspeedway and his No. 5 Hendrick Motorsports team could face further NASCAR penalties.
Prior to the start of the first round of Saturday's qualifying session, NASCAR announced Larson would not be allowed to participate and was sent his No. 5 Chevrolet Camaro back to the Cup Series garage.
A NASCAR spokesman said the team was penalized for making an unapproved adjustment to the roof rail of the car while it was being pushed from the garage to the grid.
Any additional penalties for the incident would be announced next week.
Without taking part in qualifying, Larson will lose pit selection and start from the rear of the field. Larson will start 38th, which hasn't happened since the 2018 Daytona 500. He has never won in 18 previous starts at the 2.66-mile Talladega Superspeedway, finishing as high as fourth.
Larson had been on a roll of late, winning the pole at Richmond, Martinsville Speedway and last weekend at Texas Motor Speedway. He has one victory this year, which came at Las Vegas Motor Speedway, and currently leads the regular season championship.
Front Row Motorsports' Michael McDowell ultimately earned pole position for the race, leading fellow Ford drivers Austin Cindric and Todd Gilliland.
Earlier this season, the Stewart-Haas Racing Fords of Noah Gragson and Ryan Preece were each docked 35 points after NASCAR discovered altered roof rail deflectors on each car during inspection at Atlanta race weekend, which is another drafting track.
