With third tight end Garret Celek doubtful with a hamstring strain, the 49ers today elevated another tight end, Derek Carrier, from the practice squad to the 53-man roster. Carrier is likely to get his first-ever NFL regular-season snaps Sunday against the Saints. Whereas Celek was used sparingly in the passing game at Michigan State (14 carrier catches there), Carrier has the opposite college background. He played receiver at Division III Beloit College in Wisconsin where he caught 75 passes for 1,250 yards and 12 touchdowns as a senior in 2011. He was used as a wide receiver when the Raiders signed him following the 2012 draft.