A NASCAR official said after the race that a Johnson crewman was being investigated for modifying the side skirt on Johnson’s car during the race.

MORE: All-Star Race moments | Did Denny jump final restart? | Owens: Hamlin’s pit crew the real winner | Hamlin holds off Harvick

NASCAR implemented new rules prior to this season preventing teams from modifying the side skirts during a race. NASCAR also has new video cameras monitoring pit road, making such rules violations easier to detect.

Any possible penalties would be announced next week.

Johnson, a four-time winner of the all-star race, finished 15th Saturday after slapping the wall early in the race.