This is a very simple baseball drill. You just want the left foot to hit as, or right before the ball hits the glove. We do this to prevent from getting in the fielding position too early and “getting stuck”. I talk about this in the feet section of the Fielding Position article. This drill will especially help if your team is playing on tough surfaces.
If you’re just introducing this drill only focus on the timing. After initially doing the drill with your players, you can start to address some problems that may come up like right eye, hand position, flipping etc. I would recommend coupling this drill with the down, up drill. The down, up drill sometimes gets the fielder in the correct fielding position a little early (which is ok for that drill), but this drill will work to counteract that and bring us to a happy medium when it comes to timing.
*As always feel free to comment and let me know what you think.