I think teams call the player in the first couple of rounds, when there is a lot more "show" to the draft.In the later rounds, the time limit for getting your picks in is much shorter, and thus, the team's banging their heads making sure that everyone agrees with who their best pick is at that particular point, and before that, on the phones working on trade possibilities. It's really hectic, and because it's so fast and so fluid, teams probably wont call a player ahead of time on the 2nd day.