For now, we're in decent shape with JG, Willson, and Vannett. Asking a skill player to put on 25 pounds is kind of unreasonable. Jimmy is one of those rare guys who can maintain good mobility with 250+ pounds on his frame.
Vannett has shown some promise this season. Assuming JG moves on, we'll have to do something to have a 3rd TE maybe, but there would still be the draft. I'm not too afraid of a future based on Willson and Vannett plus a FA/draft pick.