Posluszny's pending addition, which can become official Friday when NFL teams are allowed to sign unrestricted free agents, should provide a run-stopping presence to the Jaguars' defense.
The former Buffalo Bills starter has had his share of injuries and isn't the most fluid athlete, but is regarded as a tough, coachable player who draws high marks for his character.
Jaguars general manager Gene Smith is big on adding that type of personality to his locker room, signing defensive end Aaron Kampman to a lucrative deal last year.
The Jaguars now won't have a need to retain middle linebacker Kirk Morrison, a free agent. It has also been reported that Jacksonville's 4-3 defense was an appealing factor to Posluszny.