Out Approach - Getting in position to Swing. During the In Side Out Approach hitter gets in position to swing while still having complete control of the club head. This is the stage where hitter must make judgments of the speed, location, spin etc. of the ball.
Hitter moves into the pitch with both eyes in position to see the ball.
If body is jerky eyes will not get a good look at the pitch. The more the hitter knows about the pitcher, umpire, game situation, count etc. The swing can always be stopped at the last split second. Both eyes are on the ball. Even after locating the ball the front shoulder is still in.