In swings with Bat Drag, hitters try to do too much with their back elbow. That causes their back elbow to slide forward of their back hip and lengthens their swing.
What's interesting about the swing of Ben Hogan, and many other golfers, is that their swings are guaranteed to prevent Bat Drag.
In the clip below of Ben Hogan, notice how his back elbow goes to his back hip and then stays at his back hip, which causes the barrel to immediately and quickly Whip around his hands.
You can see the same thing in the swing of long-distance driving champion Jamie Sadlowski.
If a baseball player with Bat Drag learned to do what Ben Hogan and Jamie Sadlowski do, then their Bat Drag would go away.
Of course, Stan Musial did the same thing that Ben Hogan and Jamie Sadlowski do, and didn't have a problem with Bat Drag, which is why I came up with my Stan Musial Drill.