Bass finished the preseason with ten tackles, a sack and a forced fumble for a team that lacked a pass rush in 2012.
The Raiders were 31st in the league with 25 sacks last season, and were 20th in pass defense while allowing 28 touchdown passes.
Bass was an All-American defensive end at Missouri Western, and set school records with 40.5 career sacks and 50 consecutive starts.
Running back Michael Hill also had a prolific career with the Griffons, but was waived by the Chargers Saturday.
Hill rushed for 62 yards on 21 carries during the preseason.
In his senior season at Missouri Western, the Central High School graduate rushed for 2,168 yards, and was a Harlon Hill Award Finalist.