The appear to have lost left tackle to a serious knee injury for the second time in 10 months.The team in Sunday's defeat to the , NFL Media Insider Ian Rapoport reports, via a source informed of his situation. Long will undergo an MRI Sunday night to confirm the injury, which is to the same knee as last season's ACL tear.Signed to a in Enes Kanter Jersey March of 2013, Long has been a free-agent bust in St. Louis. Long is a likely offseason cap casualty, as $4 million of his scheduled $9.25 million salary if he's on the roster on the fifth day of the league year, per Mike Garafolo of Fox Sports.With Long and versatile veteran (shoulder) both out of the lineup, rookie was forced to shift over to ' blind side during Sunday's game.Robinson practiced at left tackle in September prior to joining the starting lineup at left guard. Since Long's future is up in the air, the might as well give Robinson a chance to establish himself as the long-term solution.Track all the latest injuries in our all-encompa sing . Find more Around The NFL content on . Trevor Ariza Jersey