what do you think of a left handed pitcher changing positions on the rubber from left side to right side to middle to throw the batter off? Would it work or mess the pitcher up?

I thinks that's a dumb idea!

It would probably mess you up more than it would the batter! If you want to upset the batter, keep him off balance with a change of spped and location.

I was recently discussing this with Major League pitcher Jason Grilli and have had many conversations with other professional baseball players about which side of the rubber to pitch off. See what he had to say by clicking here

The article is old and all the way at the bottom of the page. I hope this helps! He helped me a lot! Good Luck!