NEW YORK -- Oakland Raiders Pro Bowl defensive tackle Darrell Russell faces a one-year suspension by the NFL after testing positive for the drug Ecstasy, according to a league source who spoke on the condition of anonymity Sunday.

Russell, who sat out the first four games this season for violating the league's substance-abuse policy, will appeal the suspension on Thursday. He will be allowed to play until the appeal is decided.

Russell returned to action Oct. 14 after being suspended in August when the NFL determined he failed to comply with its drug-testing policy.

The 6-foot-5, 325-pound lineman in his fifth season out of Southern California, said he wasn't home when a test was scheduled to be administered, and that he failed to get back to the league on time. He forfeited about $448,000 in salary due to the suspension.

The league began testing this season for Ecstasy, a mood-altering drug popular on the nightclub scene.

The NFL does not disclose details of substance-abuse violations. Its policy covers a wide range of issues, including the illegal use of drugs and the abuse of alcohol, prescription drugs and over-the-counter drugs.

The policy also includes a series of drug-testing regulations.

Greg Aiello, an NFL spokesman, declined to comment on Russell's case.

Ecstasy, the increasingly popular party drug, affects serotonin, a brain chemical that regulates mood, emotion, sleep, appetite, memory and sexual behavior. The drug typically induces feelings of euphoria, increased energy and sexual arousal, and makes people feel a need to be touched or hugged.

The illegal drug, known scientifically as methylenedioxymethamphetamine, or MDMA, is also said to suppress the need to eat, drink or sleep, making it possible to party for two or three days.

However, in high doses it can cause a sharp increase in body temperature, leading to muscle breakdown, kidney and heart failure, and death.