Eagles running back Dion Lewis is on the trade block, according to NFL sources. At 5-foot-8 and 195 pounds, Lewis does not have the size preferred by coach Chip Kelly in the Eagles’ new system. Lewis, a fifth-round pick in 2011, has 171 yards and 36 carries, and was behind LeSean McCoy, Bryce Brown, and Chris Polk on the team’s depth chart last season. When Kelly discussed the Eagles running backs at last month’s league meetings, he specifically mentioned McCoy, Brown, and Polk, and did not mention Lewis. If Lewis is dealt, the Eagles would have only six players remaining from an 11-man 2011 draft class.