The loss of Merriman, whose hard hits earned him the nickname "Lights Out," is a big one for a team that has Super Bowl expectations.
Merriman's decision came two days after he had only two tackles in a shocking 26-24 loss to the Carolina Panthers and barely resembled the player who had an NFL-high 39 1/2 sacks in the previous three seasons and played in three straight Pro Bowls.
Merriman (Maryland) didn't immediately return
e-mails and telephone calls seeking comment.
"Shawne informed me he did not feel right and thought it best to shut it down," Chargers general manager A.J. Smith said in a statement.
Late in training camp, Merriman said the posterior cruciate and lateral collateral ligaments in his left knee were torn but that he had decided against surgery.
Second-year pro Jyles Tucker is expected to take the spot of Merriman, whose rehabilitation will likely be six to seven months.
Ravens:: Cornerbacks Fabian Washington and Derrick Martin were reinstated after serving one-game suspensions for violating the NFL's personal-conduct and substance-abuse policies, respectively. To make room for Washington and Martin, the Ravens waived offensive tackle Mike Kracalik and kicker Steven Hauschka. The team also signed tight end Edgar Jones to the practice squad and cut tight end Nate Lawrie from the practice squad. EDWARD LEE
Titans: : Jeff Fisher said the team didn't have the luxury of waiting to be sure about the safety of quarterback Vince Young before calling police for help in finding him. That led to four hours of uncertainty Monday night before Young contacted the Titans and met with Fisher, a psychologist and police crisis negotiators at the team's headquarters before driving himself home. Combined with Young's reaction to being heavily booed in Sunday's opener, his mental state has been questioned heavily the past two days. "We can never be too careful sometimes, and sometimes you can't jump to conclusions. You have to wait on information and be patient," Fisher said last night on his radio show. "The information I had didn't afford us any patience." The only thing known for sure? Young has a sprained medial collateral ligament in his left knee, and Fisher said the quarterback will not play Sunday at Cincinnati. The coach would not give a timetable past that.
Patriots:: One day after losing Most Valuable Player Tom Brady for the season with a knee injury, coach Bill Belichick says he's in no rush to sign a new quarterback. The coach said quarterbacks Tim Rattay and Chris Simms were in Foxborough, Mass., on Monday, but they didn't work out or take physicals.
Jaguars:: The lead detective in the shooting of offensive tackle Richard Collier said investigators believe the player was targeted. Sheriff's Detective Dennis Sullivan said Collier remains in critical but stable condition at a Jacksonville, Fla., hospital. He was shot in his car outside an apartment Sept. 2. Sheriff John Rutherford also said police do not believe the shooting was the result of any earlier confrontation at a nightclub. ... Looking to bolster their offensive line, the Jaguars signed veterans Milford Brown and Chad Slaughter. Slaughter signed with the Ravens in July and was released in final cuts.