Watkins and soccer player Amadou-Tidiane Daniel Dia were stopped by university police after an officer saw the car scrape a curb and the temporary license tag was not lit. The police report said an officer smelled marijuana in the car and a subsequent search found two pills for which Watkins did not have a prescription.
Dia was charged with marijuana possession.
Watkins apologized and said he'd accept any penalties from Tigers coach Dabo Swinney or the university.
''I made a mistake last night and I am truly sorry for my actions,'' Watkins said in a statement. ''I let the team down, the coaches down and this university down.''
Swinney learned of the arrest Friday morning. He said he'll gather information before deciding on any punishment. Watkins ''is a good young man who has been a model student, citizen, player and teammate,'' Swinney said. ''This is a reminder that good people make poor decisions. But, there are consequences for your actions and there will be in this case.''
Clemson men's soccer coach Mike Noonan said Dia would face punishment for the arrest, which ''go against the values'' of the program.
Watkins set Clemson records with 82 catches for 1,219 yards and 12 touchdowns. The freshman was a big reason for the Tigers 8-0 start on the way to their first Atlantic Coast Conference title in 20 years.
An officer stopped the white Cadillac that Watkins was driving and, after smelling marijuana, asked the player if there was any reason the car might smell like marijuana. Watkins said, ''No, I just got the car not long ago,'' according to the police report.
Watkins consented to a search of the car and a pat down. Officers found two pills, one for Adderall and the other for Vyvanse, both which Watkins said he did not have a prescription for. The report said officers also turned up a brown medicine bottle and a hand-rolled marijuana blunt beneath the carpet in the trunk. Both Watkins and Dia had plastic bags of ''green plant like material believed to marijuana,'' on their bodies, according to the report.