James, a 2005 fourth-round draft pick out of LSU, led the Cowboys in tackles for six consecutive seasons. But his playing time reduced last year with the emergence of second-year linebacker Sean Lee.
James finished with just 44 tackles last season, marking the first time he didn't have at least 100 tackles since 2005.
James re-joins defensive coordinator Wade Phillips with the Texans, whom he played for in Dallas for four seasons. During that time, James picked up 448 total tackles and 13 sacks.
His best season came in 2008, where he produced a career-high eight sacks and three forced fumbles and garnered Pro Bowl consideration.
James, a team captain, was a trusted veteran in the locker room and helped organize weekly team dinners with the defensive players. He also became the first Cowboys defensive player to lead the team in tackles for four consecutive seasons.
Phillips reduced Ryans' playing time as the season progressed, but the Eagles plan on using Ryans on all three downs.