Campbell's signing is expected to be announced Friday, according to the Arizona Republic and NFL.com. It will provide salary-cap relief for signing rookies and extensions for other key defensive players.
The deal, which is worth $55 million, according to NFL.com, is expected to lower his salary-cap figure from $10.7 million. That figure was set when Campbell had the franchise tag placed on him earlier during the off-season.
Campbell, 25, had a career-high 72 tackles and a team-leading eight sacks last season. He also forced two fumbles, recovered one, had his first career interception and blocked three field-goal attempts.