Like many, I've been checking the Roundrock Express box scores to see disappointing lines from Ranger top prospect Joey Gallo. Gallo is in the midst of a slump where he has been striking out close to 45% of the time and his whiff rate is soaring. This prompted me to take a close look into any current video I could get a look at to see if I could find something problematic and it immediately jumped out. Joey Gallo seems to be consistently tucking his left elbow too soon in the swing causing something called bat drag. Bat drag is simply when the back elbow gets in front of the knob of the bat in the early parts of the swing.
Bat drag is often a result of a player's hips pulling their arms through the zone. This pulling motion in itself is not a bad thing, but the upper body mechanics have to be consistently solid in order to prevent issues. With bat drag, the back elbow drops too early in the swing and pulls the bat head down causing the bat head come up at an even harsher angle through the zone as shown here:
And then the extra upward plane on his swing:
It's possible to be successful, but it is extremely unlikely and Mark Reynolds or Chris Carter is probably the best case scenario for someone with any significant bat drag.
Arm barring, pulling the arms through the zone with the hips by pulling the straightened lead arm instead of engaging the hands, is more a difference in hitting philosophy than it is an issue, but when a player's swing includes the straightening out of the lead arm it sacrifices precise bat control for extra separation and power. Barring can also cause a swing to lengthen out and is often referred to as a "long swing". That being said, many of the best hitters in the MLB practice this and a new generation of hitting may be around the corner. Gallo probably shares hitting philosophy with Josh Donaldson:
The main issue arises when a guy like Gallo, with a longer swing path, is starting his swing by dropping the elbow before his hips have engaged:
As a result Gallo's swing takes longer to get to the contact point forcing him to try and hit the ball way out in front of the plate or "cheat" by starting the swing early. In addition, the bat angle drops significantly when the elbow tucks too early causing the swing to cover a miniscule portion of the plate. In the next two series of images, notice where Gallo's bat angle is in relation to his hands when compared to Josh Donaldson. Gallo's lower body mechanics are excellent; his head stays on the ball through the zone, and he adjusts shoulder planes to compensate for high/low pitching. When his elbow tucks early and drops the bat head too quick, it makes it almost impossible to consistently make contact.
Here are a couple examples of Gallo's elbow movement from 2013-2014 showing that this isn't exactly a new issue for Gallo:
Bat drag is a fairly serious issue. I have read before that the reason you don't see too many draft prospects with bat drag because the ones that did couldn't hit high school pitching. Luckily it is a pretty easy thing to fix with repetition once you know the issue is there. It's easy to see why hitters can fall into this habit; bat lag, the way the bat stays behind the hands during the early rotational part of the swing, is an important mechanic. It's important when practicing this mechanic that the elbow gets into a tucked position to create the angle required at the point of contact. Gallo is simply dropping the elbow early and dragging the bat through the zone with the back hand and creating an even harsher angle. Gallo has a long time to figure it out and when he does, it will be interesting to see what his swing can accomplish in the MLB.