Teams usually draft quarterbacks for their physical gifts. How well they throw. How fast they run. How durable they are.
Teams usually don't draft quarterbacks for their mental gifts, because players can develop those, supposedly. Can learn how to read defenses and go through progressions and find the open receiver. Can learn how to process information quickly and accurately on the field from the pocket.
In that case, the 49ers should draft the quarterback with the best physical tools, because those can't be taught. And this year, the quarterback with the best physical tools is Justin Fields. He's a fabulous dual-threat quarterback who could have been a professional baseball player.
But he doesn't process information quickly. Doesn't get from A to B in a timely manner. Doesn't see lots of open receivers.
Is Fields merely inexperienced? Perhaps -- he started only 22 games in college. Can he improve his processing with reps while working with an offensive guru such as Kyle Shanahan? Surely Shanahan can teach him, right?
Not so fast.
What if the ability to process information is a physical gift? What if "mental quick twitch" is as real and God-given as physical quick twitch? What if some quarterbacks' brains just work faster and more efficiently than others in the heat of battle?
I'm not a player or a coach, but I notice that Shanahan has coached Jimmy Garoppolo for four years, and Garoppolo hasn't improved his mental quick twitch. Doesn't get from A to B faster or find the open receiver more efficiently than he did when he first got to the 49ers. If anything, he has regressed.
So I wouldn't count on Shanahan teaching a toolsy athlete how to play quarterback. I would expect Shanahan to draft a quarterback who knows how to play the position already, and whose neurons fire quickly.