The following is an excerpt from Pages 50-52 of Hitting Right- The Complete Hitter's Manual

"During my years 10 years of pro baseball with six different organizations, the word ‘rotate’ was seldom, if ever heard. Why do you think this is? There is definitely a rotational movement in the swing. The truth is: what you think you are doing can cause you to make the correct move—even though video may show that something else is happening.

For example: if you are thinking to swing straight down to the ball, while keeping the barrel above your hands until contact (‘Linear hand’ or ‘A to C hitting’)—it can be a good thought because you are telling yourself to be quick to the ball. Great Major League hitters can be found in pictures all over the internet posed in this contact position with the bat barrel above their hands at contact. The confusion sets in when you look at film and realize that this position is never achieved on a full swing—the barrel is always below the hands at contact during a full-speed swing (‘rotational’).

How can this be the case? These are great hitters—how can they be trying to do one thing and in reality be doing something else?

The answer is that the pictures on the internet showing contact with the barrel above the hands are being taken in paused frames while the hitter has a firm grip on the bat —not during an actual swing of the bat. In other words, these hitters are demonstrating—in slow movements and still frames—how they think they swing and where they think the barrel is during a game swing. They are showing where they want the barrel to be at contact.

In reality, during a game-speed swing, the barrel is accelerating quickly down into the hitting zone and the grip is loose. The swing flattens due to the combination of the rotational force of the hips opening, and gravity pulling the accelerating bat barrel downward against the minimal resistance of a light grip. This brings the head of the bat below the hands AND causes it to trail the hands (bat lag). When you slow down a good swing on video, you will see this happen every time. The barrel of the bat is never above the hands at contact—only on a high pitch is it even close.

Does this mean that you should change your thinking to drop the back side and drop the bat behind and below your hands—while trying to swing up to the ball? Absolutely not. If you thought this way, it would cause the bat to drag and your swing would be too long to the ball.

Does this mean that the great hitters demonstrating on the internet are wrong? Absolutely not. Thinking of being quick to the ball is still the correct way to think.
The correct thoughts make the correct thing happen—even if during a game-speed swing the physics involved cause the swing to show something slightly different than the way the hitter thinks he is swinging. I always thought I was totally a ‘linear’ hitter and that my hands went straight down to the ball. Yet, people described me as having a “natural slight uppercut” in my swing through the hitting zone. This was true—but totally the opposite of my intentions.

Depending on what you choose to see, you could single out types of ‘linear’ and ‘rotational’ movements in any good swing. The beginning back movement in a swing is ‘linear.’ So is the beginning of the weight transfer forward that comes with the stride. But, the moment the foot hits the ground from the stride, the spine stays vertical (or slightly leaned back towards the catcher) and the swing is technically ‘rotational’ from touchdown of the front foot through contact. It would be difficult to swing only ‘linear’ or only ‘rotational’ and have a good swing. This is why I choose to stay away from these terms and focus on each hitter’s individual swing flaws and thoughts.

When the actual swing is executed—it happens fast. Many physics laws factor in. It is hard (but not impossible) to change something during the actual swing. This is why the load is the key! The position of your body, where and when the weight is moving, the timing of the load, and your overall mental frame of mind have more of an effect on your physical swing than anything you can change once you are actually swinging.

Maybe this is the best way to sum it up: I have read many hitting books. The most complete ‘rotational-only’ book and the most complete ‘linear-only’ book I have ever read, both use many of the same Major League hitters to try and strengthen their arguments against the other."

Hope this helps. I saw this over and over as I wrote my book. I asked 6 kids to show me in frames how they thought they swung the bat, and then I took video and slowed it down. Totally different.