The Raiders signed veteran guard Daniel Loper on Friday in a move that gives them more depth and experience. Loper, 28, played in 40 games for the Tennessee Titans from 2006-08 and eight for the Detroit Lions last season. His only five starts as an NFL player came for the Lions. Robert Gallery and Cooper Carlisle are the projected starters at left and right guard, respectively. Loper will compete for a backup spot during training camp.