The San Diego Chargers had depth issues at OLB. Today, they took a step to address that issue. They still have Shaun Phillips as one starter in addition to Larry English, Antwan Barnes and Travis LaBoy coming in as contributors. The key missing ingredient was a player who could play on 1st and 2nd downs, play well in the run game, and drop back into coverage as needed; Jarret Johnson is that guy.
The terms of the deal are unknown at this time, other than the length of the contract being 4 years, but this is most likely going to be the only signing the team makes for the OLB position. Players with gaudy sack totals — like Mario Williams — will sign elsewhere and were always long shots to play in San Diego anyway. Instead, the Chargers will rely on Phillips, Barnes and English to provide the pass rush with Johnson getting a lot of snaps in non-obvious passing downs. This will keep the players who are better at rushing the passer fresh, and leaves fewer snaps for LaBoy, who got exposed often last year (assuming he doesn't get cut before the season).
Jarret Johnson played his entire 9-year career with the Ravens and last year was coached by Chuck Pagano, the brother of current Chargers Defensive Coordinator John Pagano. He's been the Ravens starter at OLB for the 5 years and didn't miss a single game in that stretch. He has 20 career sacks, with his highest season total being 6.
The Chargers also re-signed Kory Sperry. They declined to offer him a restricted free agent tender, but instead signed him to a 1 year contract today. He'll likely reprise his role as 3rd string TE as the Chargers look to free agency or the draft to find Antonio Gates' backup.