Opening Up to Early?

I am a varsity high school coach; and am running into trouble this year with some players wanting to open up as soon as they make the first movement. Are there any drills to help keep them closed up more as they are moving towards the plate? Would putting them back agaist a wall help this? Thanks!

My pitching taught this two ways -

First, he stressed a firm glove side arm - over & over.

Next, he always talks about using the lead elbow as a site - lock it onto the target and keep it there as long as possible. Whenever, I fly open - I think about these two cues and usually keep closed on the next throw.

Try to figure out what it is that’s causing them to open up early and fix that. It may be something different for each pitcher.

Common causesof opening up early include lack of postural stability, lack of glove stability, and lack of momentum down the hill.

One thing we do is put a peice of white tape down from the pitchers rubber straight out about 8’, then have then pitch. This tells us if they are landing open or if they are closed and throwing across their body, or if they are staying right where they need to be. Just depends where they land. Landing on the tape strip is a good thing.