Eric Maycroft, the front tire changer for Michael Waltrip Racing's No. 56 Sprint Cup team, has been suspended indefinitely by NASCAR for failing his drug test Aug. 16 at Watkins Glen.

Maycroft violated Sections 12-1 (actions detrimental to stock car racing) and 19 (Violation of the NASCAR Substance Abuse Policy), according to NASCAR. He has been replaced by Terry Spalding starting this weekend at Bristol Motor Speedway.

Maycroft was the tire changer for Martin Truex Jr., who is 12th in Sprint Cup's points standings. Truex won at Sonoma in June, making him eligible for one of the Chase's wild-card spots. He trails series leader Jimmie Johnson by 160 points.

Maycroft, 32, a former pitcher for Wake Forest University's baseball team, has been terminated by MWR in accordance with the company's zero-tolerance policy. However, the company said it "fully supports NASCAR's substance-abuse policies and those who complete the Road to Recovery program."