NASCAR driver A.J. Allmendinger will begin his road back to the sport on Friday.

The manager for Allmendinger, Tara Ragan, said the driver will be evaluated by a doctor, as part of NASCAR's "Road to Recovery" program.

The doctor will then develop a specific plan for Allmendinger, Ragan said.

Allmendinger was suspended earlier this month for violating the sport's substance abuse policy.

Ragan said Allmendinger tested positive for an amphetamine, but said they still do not know what substance triggered the positive result.

"What is that?" Ragan questioned. "We're trying to find that needle in the haystack so we can retrace those steps and find out what may have happened. But honestly, we don’t know."

Allmendinger was suspended in early July after a random drug test.

He can be reinstated once he completes NASCAR's recovery program.