Former NFL defensive lineman Dana Stubblefield pleaded guilty Friday to lying to investigators in the BALCO steroids case, making him the first football player charged in the long-running federal investigation.

Stubblefield, a three-time Pro Bowl player who testified before the BALCO grand jury in November 2003, was charged with making false statements to federal agents about his use of performance-enhancing drugs.

The charges were unsealed Friday in federal court in San Francisco. They allege Stubblefield made false statements to an IRS agent when he said he had not used steroids linked to the Bay Area Laboratory Co-Operative and denied receiving performance enhancers from BALCO founder Victor Conte.

The 37-year-old Stubblefield pleaded not guilty and was released on bail. He returned to court later Friday to enter his plea to the false statements charge. The deal calls for him to spend zero to six months in prison.

Stubblefield and his attorney, Mike Armstong, declined to comment as they left court.

Stubblefield is the latest target in a federal investigation that has spanned five years and ensnared several elite athletes and members of the Burlingame-based steroids distribution ring, including Conte, who served four months in prison.

Barry Bonds, the former San Francisco Giant and baseball's career home run king, has pleaded not guilty to perjury and obstruction of justice charges and is awaiting trial.

Stubblefield played on the defensive line for the San Francisco 49ers, Washington Redskins and Oakland Raiders from 1993-03, and was the NFL defensive player of the year in 1997 while with the 49ers.

He was one of three players fined by the NFL for testing positive for the designer steroid THG, but he was not suspended because THG was not added to the NFL's banned substance list until after the tests were conducted.