What infield depth should mean to a 3B coach?

Infielders can position themselves in a variety of different positions to defend ground balls WITH A RUNNER ON 3RD BASE. The primary positions are "in", "1/2 way or double play depth, "corners in" and "back". There are certainly different variations to these four but these are the basic ones.

If the infield is in, the 3B coach should be aware that they are attempting to prevent the runner at 3B from scoring. The infield often plays this way without a double play opportunity or if the runner at 3B is critical to the games outcome. In most cases, the 3B coach should keep the runner at 3B on groundballs. Exceptions to this rule are aggressive ones. With 1 out, a 3B coach might be more aggressive on sending his runner despite the infields "in" position.

If the infield is playing half way, then they will be reading the speed of the hit and deciding who to go after on ground balls. Hard hit balls give them an opportunity at the plate while slow hit balls should go to 1B. I like the "contact" play on this depth.

When the corners are in, the safety squeeze becomes less of an option. Also, the primary read in this situation is score on all ground balls up the middle. If the ball gets by the pitcher on the ground the runner at 3B should break because the middle infielders are conceding the run.

The final depth is back. This is the easiest read. The infield is conceding the run. Therefore, the contact play is a definite. Send the runner on all balls hit on the ground.

Sometimes, poor coaches will play their infield in when they shouldn't. The infield in should only be employed if you're losing, in a tie game, or winning by a run. It situations other than that there is no need to cut down the runner at 3rd. Sometimes, poor coaches make you rethink your strategy on what to do with the lead runner.