Championship-winning crew chief Todd Parrott has been suspended indefinitely by NASCAR after violating the series' substance abuse policy.
Parrott, who currently serves as crew chief on the #43 Richard Petty Motorsports entry for Aric Almirola, will be replaced by RPM's vice president of operations and competition Sammy Johns until further notice.
Parrott will be permitted to return to competition upon completion of NASCAR's Road to Recovery treatment programme.
"We have an expectation of all RPM employees to conduct themselves at the highest level of professionalism and within the competitive confines as set forth by NASCAR," Johns said.
"We are very disappointed that one of our employees did not meet our expectations and we completely support NASCAR, their policies and final decisions when it comes to the substance abuse policy."
Parrott helped Dale Jarrett to claim the Cup title in 1999, and has also worked with former champions Bobby Labonte and Matt Kenseth.
He joined RPM in 2010, and oversaw both of Marcos Ambrose's victories at Watkins Glen.