alot of people may go after marshall but i think its a little obvious we need a 2nd TE. so with that why not take a look at scheffler. i mean the guy is young (27 opening day) he is a better then average TE who is durable (only missed like 7 games in 4 years) has great blocking skills/look at all of the 1,000 rushers denver produced over the years (probably better then keller) and if you run a 2 TE set you can keep him in to block while using keller MORE in the passing game which can help a young QB like sanchez or you can try and line keller up as a possible slot receiver. i bet when under pressure it helps to have a TE who can bail you out on a checkdown or go over the middle for you.
I would love a true #2 TE. While Keller seems to be more one dimensional...I think lining up both Scheffler and Keller would be tough to defend. Now we just bring in Hunter as another blocking TE but the defense does not have to respect the fact that he will go into the pattern. Having Scheffler would give another option to a young QB.