The bigger issue is blocking. Scheff just doesn't fit the mould. Wierdly enough (considering how pass-happy the Pats have been), the roots of McDaniels' system are very much smash-mouth, so the TE is expected to be a good blocker. Combine that with a reputation for being fragile and I can see why he'd be on the trade block.
Any team running a West Coast offense (or some derivative) should take a very close look at him, as he can do a lot of damage in the right situation.