NASCAR indefinitely suspended Xfinity Series driver Spencer Gallagher, who won Saturday at Talladega Superspeedway, for failing a random drug test.
NASCAR would not say when Gallagher failed the test or what drug he tested positive for, just that it was notified Tuesday by its medical review officer of the violation.
Gallagher, who drives for his father's GMS Racing, said it was a mistake and he would enter NASCAR's recovery program, which typically takes a minimum of four weeks to complete.
"I want to assure everyone in the NASCAR community this one-time error in judgment will never happen again," Gallagher said in a statement. "I am taking the steps to enroll in the Road to Recovery program supported by NASCAR. I would like to say that I am sorry to all of the GMS organization for my actions, especially my team and team owner, who have worked so hard this year and have put faith in me.
"I also want to apologize to NASCAR, Chevrolet and my fans for letting them down. I have not upheld the behavior that is expected of me. I promise you all here and now, I will do whatever it takes to make this right."
The win had virtually guaranteed Gallagher a spot in the playoffs, but now he will not be granted a waiver to be championship-eligible, a NASCAR spokesman said. A driver must run every race or be granted a waiver to miss races.
The team has not yet named a substitute driver for Gallagher.
"GMS fully supports NASCAR's policy on substance abuse and we do not condone this type of behavior," GMS president Mike Beam said. "First and foremost, our entire organization wants to apologize to NASCAR, our sponsors, teammates and fans due to this policy violation."