Penske Racing says Brad Keselowski's car at Dover failed a post-race inspection because of a broken part in the front of his Ford.
Keselowski finished fifth in Sunday's race and NASCAR said afterward the entire front was too low. Team owner Roger Penske said Monday the failure was due to a broken part that allowed a front spring to fall.
NASCAR addresses infractions and issues penalties on Tuesdays.
Keselowski crew chief Paul Wolfe just returned last week from a three-race suspension for using unapproved parts and is on probation through the end of the year. The typical penalty for a car being too low in inspection has been the loss of six points and a $25,000 fine for the crew chief.