Suspended NASCAR driver Jeremy Mayfield denies ever taking methamphetamines and says he doesn't know how he failed a random drug test.

Mayfield's denial is found in an affidavit that is among several hundred pages of documents filed Thursday by his attorneys in U.S. District Court. The driver was suspended indefinitely by NASCAR May 9 for failing a random drug test conducted eight days earlier at Richmond International Raceway.

He is suing NASCAR for immediate reinstatement, and his next court date is July 1.

NASCAR is countersuing and alleges Mayfield breached his contract and defrauded NASCAR and its competitors of earnings.