Flanagan finished his rookie season with one catch for 14 yards in three games.
The undrafted rookie out of Pitt didn't survive the preseason in Washington but eventually joined the 53-man roster when Jordan Reed (foot) and Vernon Davis (concussion) were unavailable in December. Flanagan will need to battle for a roster spot in 2019, presumably hoping to land a job as a blocking-focused No. 3 tight end.
Flanagan signed with the Redskins as an undrafted rookie in May but failed to survive roster cutdowns. The 23-year-old rejoins the team with starting tight end Jordan Reed (foot) ruled out for Sunday's game, and should serve as the team's No. 3 tight end in while Reed is sidelined.