He's coming off knee surgery. He's missed 12 games in his first two seasons. He's playing on a team with a quarterback in bad standing with the head coach.
The two top receivers on his team combined for 200 targets last year, and the top three saw 273. The tight end behind him on the depth chart outperformed him last year and should be in the mix for snaps this year as a result.
He didn't score a single touchdown despite hauling in 50 passes and seeing 10 red zone targets in 11 games last season.
He's 6'3" and 237 pounds, yet he's not very athletic.