There is "some doubt" within the Chargers organization that running back Ryan Mathews will ever become the player the team envisioned when he was drafted 12th overall three years ago. SOURCE: San Diego Union-TribuneFantasy Spin:Mathews broke his clavicle twice last season and missed four games. When he was healthy, he was replaced at times by Ronnie Brown on passing downs and lost carries to Jackie Battle after an early-season fumbling problem. With GM A.J. Smith and coach Norv Turner no longer with the organization, Mathews will have to prove his worth to the new regime in 2013.