A popular saying by coaches is is "if it is 95 down the middle big leaguers will hit it a long way.
This is correct but only somewhat. People act like big leaguers would hit 700 with 50% homers on pitches in the middle quadrant but if you look at chapman and pitches right down the pipe the league hits about .350. Sure if he just threw there he wouldn't be a big league pitcher as a .350 ba against is bad but this still means 65% of the time big leaguers will make an out on those pitches and in fact those 80 grade fastball types do still get swings and misses on pitches down the pipe.
Of course they can't throw down the pipe every time but if you have a plus plus fastball and a good secondary you can get away with some fat pitches as long you throw the ball regularly in the box and don't fall behind too often.