I am beginning to wonder if Harper has much talent at all. Maybe he was just a precocious teenager who has now leveled off.
That's certainly possible, but I think it's more likely that he is a player who:
-- Was brought up to the Majors at 19 and proceeded to have a very good year by today's standards for MLB players (+118 OPS) and an historic one for his age.
-- Had an OPS over 1.000 in his second year when he ran into the wall in Los Angeles, wound up missing more than 30 games and was never the same once he returned.
-- Had another major injury early in his third season, and has not yet returned to form since he returned to the lineup. without endorsing the 100 ABs theory, I do think it's fair to say that he's dealing with a lot, especially for someone who wants to be the best and expects himself to be the best.
Two major injuries in your first three years in the majors -- especially when caused by the aggressiveness which is your basic nature -- could mess with your head. The injury to the thumb may still be bothering him, and he certainly is worried that it's not completely healed as seen from his reaction on that diving catch he made over the weekend.
Most importantly, he's 21, and he's still got a lot to learn. Yaseil Puig is two years older and making many of the same mental mistakes (but he's hitting). Anthony Rendon was learning base running and defensive lessons at Harper's age by playing in college -- well, actually he was sitting out the college baseball season with an injury. When Werth, Desmond and LaRoche were 21, they were making their blunders in front of a few hundred people in the low minors.
Yes, guys like Trout and Ryan Zimmerman show an instinctive feel for the game at a very early age, but most have to learn through their mistakes.
Here's my prediction: Harper reins it in somewhat over the rest of the season, but still plays aggressively and makes some more mistakes. But at some point before September, he starts hitting the way most of us think he's capable of, and pretty much all the other stuff is forgiven.