The Chargers, who have the NFL's eighth-highest prices, say more than 6,500 general-admission tickets remained unsold at Thursday's deadline.
It's San Diego's second blackout in two home games. The Chargers' string of 48 consecutive sellouts dating to 2004, including playoff games, was snapped two weeks ago when the team fell more than 7,000 tickets short of a sellout against the Jacksonville Jaguars.
NFL rules require a blackout if a game isn't sold out 72 hours in advance.
The Chargers, Southern California's only NFL team, say there could be several games blacked out this season.
Copyright 2010 by The Associated Press
