A good defensive catcher can block balls thrown in the dirt. It's a skill keeps runners from advancing and saves runs.
You must realize that while you may occasionally catch the ball when blocking it, that's not the goal. The goal of blocking the ball is to keep the ball in front of you where you have an opportunity to keep runners from advancing on the pitch. It can be difficult to get your body in position to block a pitch when you are focused on the task. If your focus is on catching it, chances are you will not be in position to block it.
Once you determine that the pitch will bounce in the dirt, aggressively go after the ball and try to shorten the distance between you and where it will bounce. The closer you get to the point where the ball is going to bounce, the better chance you have to block it. This is a side to side, and/or slightly forward move. I say slightly forward, because if you are too aggressive moving forward, you could put yourself in danger of being hit by a swinging bat.
You may hear a coach tell an infielder, "play the ball, don't let the ball play you". This is the same advice you need to take when blocking pitches in the dirt. If you simply drop and hope the ball hits you or stab at it with your glove, you're not going to be successful most of the time.
Blocking a pitch requires quick reflexes on your part. With runners in a position to steal a base you will naturally be in a squat position that allows you to make a quick throw. This position is also important for blocking pitches. The reason it's mentioned here is that you may go back to a lower squat with a man on third, second and third, or the bases loaded. While there isn't the threat of stealing a base in these situations, there is the threat of all runners advancing on a past ball or wild pitch. So while you may not have your rear as high as you would when there is a threat of stealing, you still want to have it high enough to allow you to move quickly to either side.
The ball coming right at you is the easiest to block:
What does relaxing have to do with it? Think of it this way. If you throw a ball against a brick wall, the ball is going to bounce back to you. If you put a pad in front of the brick ball and throw the ball again, the ball will hit the pad and drop. If your chest is rigid and doesn't give when the ball hits it, the ball will act like it's hitting that brick wall and may bounce a long way. If you relax your body before impact and allow some give when the ball hits you, the ball will act more like it's hitting a pad than a brick wall.
If the pitch is going to bounce slightly to your left:
The same technique applies on a pitch to your right.
Keeping your balance should not be a problem when blocking a pitch slightly to the side. If you find that you're off balance and sometimes fall to the side when trying to block this pitch, it may be that you're dropping your knee to much in front of you instead of off to the side. When this happens, you will feel the need to learn your body to the side to try and get in position. Another reason for being off balance in this situation is trying to block a ball that is too far away by dropping your knee. With a ball that is farther away, you need to step before you drop. This technique is discussed below and on the next page.
If you determine that dropping a knee to the side will put you close to but not in a good position to block the pitch, you will want to add a small step to the technique we have already covered.
Keeping your balance can be an issue when you add this step. To help you keep your balance practice having your lead knee slide along the ground. This will help you keep your balance and with practice the sliding can put you in a better position to block the ball. Remember balance and position are essential to blocking the ball.