I apologize, was a horrible video made with my phone. He should be throwing a bullpen around Tuesday or Wednesday, will take my sports camera and get better footage. Think I have been able to figure out the issue causing the "jerk". He has always been a "pull the glove" guy. On off speed pitches I'm not seeing the jerk, only fastballs. I've been able to pause the video to see he is pulling his glove side elbow further on fastballs causing a dip in the shoulder towards first base and the head follows. The jerk I'm seeing is him quickly getting his head back on target. My belief is he is "pulling" harder on fastballs. My only concern at this point is he is taking his head off the target. Velocity and control are pretty good. I've discussed with his instructor and we're both in agreement to leave it alone through his summer season and consider any adjustments in the off season. Not really sure at this point best way to make an adjustment. Don't want him to do anything to slow the body down.