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And it makes me think about which plositions require it most. D backs, quarterbacks--obviously. Because they need to make those preliminary reads before the ball is snapped.
On the other hand, a running back may know where a play is designed to go...but every cut is decided in real time, right? You can't tell in advance if blocks are going to be made.
On your other point my coaching friend would disagree. He says that the 'mentally lazy' are identified before the draft, either by watching film, or conversations with the right people. There are no surprises on this score. Obviously a dominant talent may be drafted even if his motor and dedication are in question...but those are all taken into account before a pick is made.