Stealing signs?

[knightsb]

... Also your catcher should have a plan anytime a runner is on second. So that shouldn't be any different to swith to that system if a coach is calling pitches.

Longwood base runner signaling inside and outside pitches to the batter.

 

[Cannonball]

...and if this is the case, the pitcher should be able to throw at the inside portion of the catcher's body as an early target until the catcher slides inside just before delivery. If the hitter is watching the runner then they won't see the ball. We taught our catchers to adjust late as to not give location away. We also had a signal early in the count for our catcher to set up early slightly outside and the pitcher throw one up and in. Of course you'd better have a pretty good catcher for that.