TE's are like LB's and RB's....They are expected to play ST's as well.
I think Hopkins will fill right in to that TE #2 role. He's sat an entire year, knows the offense and is ready to take over for Everett. I bet he's a better blocker as well.
Harris, "IF" he wants to make the squad, he'll have to be a ST's STUD! Then, I bet McVay will have a few RedZone packages for some endzone mismatches using Harris and his height. Again, only if he's ready. He could be a red shirt experiment, but I think Mcvay wants him to do a little more his first season and get him involved catching the ball in special situations.