Moeaki was a third-round pick of the Kansas City Chiefs in 2010. He caught 47 passes for 556 yards and three touchdowns as a rookie but has battled injuries since, including a torn ACL that wiped out his 2011 season.
The 26-year-old spent the first several weeks of this season on injured reserve for the Chiefs before receiving an injury settlement.
At 6-foot-3, 252 pounds, Moeaki provides another option at tight end for the Bills. He is more of a receiving threat than No. 2 tight end Lee Smith and could see playing time in the final four games as the Bills look to evaluate the position heading into next season.