The way I saw it, Morris was probably supposed to run to about the 10 yard line. When he carried his route to the post, Davis had to stop his route. This allowed Peterson to jump the route.
Morris should have kept the LB low so he would not have been in the passing lane to Davis, allowing him to keep running the post route.
I was at the game, and from where I sat, the middle of the field was wide open. Nobody draws up passing combinations like that.