Believe me, they are focused on him gaining weight, they already have him on a special diet. With the training advancements over the last several years, he will not lose that much explosiveness as the gain will be gradual. This year, he will just be a specialty package guy. But the true effectiveness of great TE's is that can both receive and block well and their presence does not telegraph the play, which also allows for much more effective audibles. Look at what the Packers do with their TE's, that is where we are headed. His upper body is not bad, but he is very spindly in the legs, which is where they are focused. He needs to get to at least 235; he's 215 now. Will not all happen this year as noted but that is the plan. For those saying he should be a receiver, go look at this tape. He has very little experience with any route running against quality corners (and very little football experience overall); that is a completely different skillset. Will he be split out at times for iso/jump ball plays and body positioning slants, of course. Will be fun to see him in action, but in shorts at 215 lbs and with his range, this is where he is going to shine. He will come back down to earth with the pads on, but hopefully just temporarily.
