Smith spent the last four seasons with the Oakland Raiders. Known for his blocking skills, the 6'6", 265-pounder recorded 10 receptions for 73 yards and three touchdowns in 2018.
The 31-year-old played for the Bills from 2011-14, starting 34 games.
Buffalo will likely employ him in a similar fashion as his previous tenure, putting him on the field in goal-line and run-blocking situations. The fifth-round pick out of Marshall could catch the occasional pass in the red zone or in play-action situation, but Smith and the Bills know where his skills lie.
The team previously signed Tyler Kroft to a three-year contract this offseason to serve as its starting tight end. The Bills also used a third-round pick on Ole Miss tight end Dawson Knox.
The presence of Kroft and Knox makes it likely Smith will see the field in special teams and running situations almost exclusively. However, the fact that the Bills gave the Tennessee native a three-year contract is evidence they plan on keeping him around despite the depth at the position.
His signing could call into question the roster status of Jason Croom and Tommy Sweeney, the other tight ends on the depth chart.