The Chicago Bears elevated running back Armando Allen from the practice squad to the active roster, waived linebacker Patrick Trahan and terminated the contract of vested veteran running back Lorenzo Booker, the team announced Saturday. Allen played in two games for the Bears last year with 15 carries for 48 yards. He spent the rest of the season on the practice squad.Trahan appeared in five games for the Bears in 2011 with five special teams tackles. Booker combined for 230 rushing yards, 363 receiving yards and 879 kickoff return yards in 36 games with the Miami Dolphins (2007), Philadelphia Eagles (2008) and Minnesota Vikings (2010-11). The Bears active roster is at 52 players.