Who said snacks would come in and play 100% of the snaps? Make his role to plug gaps to start so that’s his job and 1/11th. Put him in on obvious run downs. You’re overthinking this. It’s not hard to give a player a small role and have them produce off the street. It happens very often.
The raiders ran the ball 19 times with their backs. Luiget’s first game in buffalo he played 17 snaps. Why couldn’t Harrison play the same amount of snaps ad luiget off the street?
If the player can’t handle what you’re asking him to do, pull him out of the game. If he can keep playing him in that role, if he can handle more give him more. Phillips freelancer because he was more of a pass rusher. A run stuffer like Harrison isn’t going to be freelancing his first week here or ever
The point is he came in and played shortly after he was signed.