Martin Truex Jr. to start at back of Daytona qualifying for violation

DAYTONA BEACH, Fla. -- NASCAR did not allow Martin Truex Jr. to make a Daytona 500 qualifying lap Sunday because of a noncompliant roof flap in the Furniture Row Racing No. 78 Toyota.

The team's car was impounded until officials could look it over Sunday afternoon at Daytona International Speedway. Truex will have to start at the rear of the field for his qualifying race Thursday, as will the Stewart-Haas Racing cars of Kevin Harvick and Brian Vickers, whose qualifying times were each disallowed because of a noncompliant track bar.

Truex crew chief Cole Pearn told ESPN.com after qualifying that beyond it being a roof-flap issue, he had no clue what penalties could come from it.

NASCAR typically issues any penalties the Tuesday after the event, so it's likely any penalties would be issued Feb. 23, following the Daytona 500. According to the rulebook, modifying roof-flap systems can be as high as a P5 penalty, which carries a minimum 50-point penalty, a minimum $75,000 fine and a minimum six-race suspension to the crew chief. Messing with a roof flap could significantly impact the air flow, especially at a restrictor-plate track, where the aerodynamic draft is key.

Last year, Dale Earnhardt Jr. and Denny Hamlin had times disallowed in qualifying because of track bar violations and were not penalized beyond having to start at the rear of the field in their qualifying race.

Truex, Harvick and Vickers will be allowed to start the Daytona 500 in the position that they earn through the qualifying races Thursday.

Harvick crew chief Rodney Childers tweeted an explanation of the team's violation and an apology for the misstep.