The Eagles have focused on the defense in the initial stage of free agency adding four players on that side of the ball Tuesday - safety Patrick Chung, cornerback Bradley Fletcher, linebacker Jason Phillips and defensive lineman Isaac Sopoaga. They also hosted former San Francisco 49ers defensive lineman Ricky Jean Francois for a visit Wednesday at the NovaCare Complex.

A former second-round pick of the Texans in 2009, Barwin led Houston with 11.5 sacks in 2011. Barwin played on both the weak side and strong side in the Texans' 3-4 defense last year. This versatility would be useful for the Eagles if the team does indeed plan to incorporate elements of that scheme.

Butler was a fourth-round draft choice of the Cowboys in 2009 and was a key reserve player in Dallas. Last season, he played in all 16 games and made two starts, recording 23 combined tackles and three sacks. Playing behind DeMarcus Ware and Anthony Spencer in Dallas, Butler still has registered 11 career sacks. The Jets are also reportedly interested in Butler.

Make sure to follow us on Twitter @EaglesInsider