Allmendinger was initially suspended July 7 before the Coke Zero 400 at Daytona International Speedway after his "A" sample collected during a random drug test the previous weekend at Kentucky Speedway also tested positive. Both the "A" and "B" samples were collected at the same time.
According to a NASCAR statement issued Tuesday evening, Allmendinger will next be provided with a letter outlining a process for reinstatement. If he agrees to the terms of the letter, he will be cleared to return to competition upon completion of the Road to Recovery Program.
"We respect NASCAR's policy and the process they have taken with this matter," Penske Racing said in a statement released Tuesday night. "Penske Racing is very disappointed with the result of the 'B' sample test and will evaluate its course of action as it pertains to AJ over the coming week."
The team also said that Sam Hornish Jr., who has filled in for Allmendinger in the last two Sprint Cup races, will drive Roger Penske's No. 22 Sunday at Indianapolis Motor Speedway and the following week at Pocono Raceway.
"This was not the news we wanted to hear and we will work to get to the source of what may have caused this," Tara Ragan, Allmendinger's business manager, said in a statement Tuesday night. "To that end, we have secured the services of an independent lab to conduct thorough testing on every product within AJ's home and motor coach to find what might collaborate with his test, which created results that were within nanograms of accepted standards.
"We are working closely with NASCAR and Penske Racing to identify the next action steps in this process," Ragan added. "We continue to be extremely grateful by the breadth and scope of support for AJ from his fans and partners. We would like to again thank NASCAR, Penske Racing and all our sponsor partners for the open communication, and for helping us at every step in this process. We expect to have further updates in the upcoming days."
Official NASCAR Release:
AJ Allmendinger, driver of the No. 22 car in the NASCAR Sprint Cup Series, has been suspended indefinitely from NASCAR for violating the sanctioning body's substance abuse policy.
On July 24,Allmendinger was found to have violated Sections 12-1 (actions detrimental to stock car racing) and 19 (NASCAR's substance abuse policy) of the 2012 NASCAR rule book.
As outlined in the rule book, NASCAR next will provide Allmendinger a letter outlining a process for reinstatement. By agreeing to the letter, he will be allowed to participate in the Road to Recovery Program.