The San Francisco 49ers have promoted tight end Derek Carrier from the practice squad to the active roster. The team announced it via Twitter. Carrier takes up the 49ers 53rd roster spot, and is expected to fill in for third string tight end Garrett Celek. The 49ers are short Celek due to a hamstring strain suffered in last week's loss to the Panthers. He is listed as doubtful for Sunday's game. They also lost tight end Vernon Davis to a concussion, but he and safety Eric Reid remain on track to play Sunday vs. the Saints. Davis and Reid are both listed as questionable, but as long as they remain asymptomatic heading into Sunday, they should play.