Losing Johnson is a bigger blow than many think because he was the most underrated player on the Ravens' defense. Baltimore will likely try to replace him with Paul Kruger, but I'm not sold on that. Kruger is a pass rusher who will have trouble setting a physical edge against the run.
The original plan was to eventually replace Johnson with Sergio Kindle, the team's top draft pick in 2010. But Kindle fractured his skull when he fell down two flights of stairs before his rookie training camp, and he's never been the same. I believe the Ravens will have to go in free agency to find someone who can do the same things as Johnson.
Never a Pro Bowl player, Johnson was tough and dependable, playing in 129 straight games the longest streak in team history and the fourth-longest currently among linebackers. His ability to rush the passer declined the past two seasons, but his impact against the run shouldn't be overlooked.
Johnson is headed to the Chargers now, but he will always be an AFC North-style player.