ALLEN PARK, Mich. (AP) - Reggie Bush is joining the Detroit Lions. The Lions introduced the free agent running back Wednesday. They did not immediately provide any details about his contract. Bush gives Detroit another speedy playmaker for an offense that already includes star receiver Calvin Johnson. He's being brought in to help improve an inconsistent running game. Jahvid Best, a first-round draft pick in 2010, didn't play at all last season, and his future is in doubt because of concussion problems. Bush adds a big-play threat to Detroit's backfield, which already includes 233-pound running back Mikel Leshoure. Bush rushed for 986 yards for Miami last season after a 1,086-yard output for the Dolphins in 2011.