http://www.mercurynews.com/breakingnews/ci_6949070 The 49ers learned today that they have lost outside linebacker Manny Lawson to a season-ending knee injury. Lawson, the second of the team's two first-round picks in 2006, was injured in practice Wednesday. The injury was not initially thought to be serious, but team doctors later discovered that Lawson had torn an anterior cruciate ligament, according to team spokesman Aaron Salkin. There was no immediate word about who would replace Lawson. Backup Jay Moore was placed on injured reserve after suffering a high ankle sprain in the exhibition finale at San Diego and is out for the season. Hannibal Navies and Parys Haralson could be among the candidates to replace Lawson. Lawson was a key figure in the 49ers' decision to switch from a 4-3 defensive alignment to a 3-4 this season.