San Diego Chargers defensive tackle Garrett Brown has been suspended without pay for the team's first four games of the 2012 regular season for violating the NFL policy on performance enhancing substances, the NFL announced Thursday. Brown is eligible to return to the Chargers' active roster on October 1, following the September 30 game against the Kansas City Chiefs. Brown can participate in all preseason practices and games. Brown's absence should not significantly affect the Chargers' defense. The 300-pound Brown, 23, has never played in a regular-season NFL game. He was signed by the Chargers in May and played in the team's first preseason game, getting one assist.