At the end of the 2011 season, Allmendinger left Richard Petty Motorsports when the driving spot for Penske Racing's No.
22 Shell/Pennzoil Dodge became open after the parting ways of Kurt Busch and Penske.
Prior to his suspension, his best finish was a second at Martinsville Speedway.

After failing a random drug test on July 7, 2012, Allmendinger was suspended from participation in the Coke Zero 400.
Steve O'Donnell, NASCAR's senior vice president for racing operations, said that Allmendinger had up to 72 hours to request a B test sample.
The next day, Penske said before the Honda Indy Toronto race that Allmendinger's B sample would be tested on Monday or Tuesday.
Allmendinger requested a B sample test on July 9.
On July 11, 2012, Allmendinger's camp said a stimulant caused the positive drug test.
The B sample test had not yet been scheduled at that time.

On July 24, it was announced by NASCAR that Allmendinger was suspended indefinitely after the B sample tested positive for a banned stimulant, which was revealed to be amphetamine.
He chose to participate in the Road to Recovery program.
On August 1, he was released from his contract by Penske Racing.
Allmendinger was replaced in the No.
22 by Sam Hornish, Jr.; he later stated that the cause of the positive test was Adderall that he had unknowingly taken, being told it was an "energy pill".
Allmendinger was reinstated by NASCAR on September 18 after completing the Road to Recovery program.

In October 2012, Allmendinger returned to NASCAR at Charlotte Motor Speedway, driving for Phoenix Racing, substituting for Phoenix's intended driver Regan Smith, who had been hired by Hendrick Motorsports to drive the No.
88 for Charlotte and Kansas while Dale Earnhardt, Jr. was sidelined with a concussion.
At the end of the 2011 season, Allmendinger left Richard Petty Motorsports when the driving spot for Penske Racing's No. 22 Shell/Pennzoil Dodge became open after the parting ways of Kurt Busch and Penske. Prior to his suspension, his best finish was a second at Martinsville Speedway.
After failing a random drug test on July 7, 2012, Allmendinger was suspended from participation in the Coke Zero 400. Steve O'Donnell, NASCAR's senior vice president for racing operations, said that Allmendinger had up to 72 hours to request a B test sample. The next day, Penske said before the Honda Indy Toronto race that Allmendinger's B sample would be tested on Monday or Tuesday. Allmendinger requested a B sample test on July 9. On July 11, 2012, Allmendinger's camp said a stimulant caused the positive drug test. The B sample test had not yet been scheduled at that time.
On July 24, it was announced by NASCAR that Allmendinger was suspended indefinitely after the B sample tested positive for a banned stimulant, which was revealed to be amphetamine. He chose to participate in the Road to Recovery program. On August 1, he was released from his contract by Penske Racing. Allmendinger was replaced in the No. 22 by Sam Hornish, Jr.; he later stated that the cause of the positive test was Adderall that he had unknowingly taken, being told it was an "energy pill". Allmendinger was reinstated by NASCAR on September 18 after completing the Road to Recovery program.
In October 2012, Allmendinger returned to NASCAR at Charlotte Motor Speedway, driving for Phoenix Racing, substituting for Phoenix's intended driver Regan Smith, who had been hired by Hendrick Motorsports to drive the No. 88 for Charlotte and Kansas while Dale Earnhardt, Jr. was sidelined with a concussion.
A. J. Allmendinger