Julio Teheran leads the MLB with eight pick-offs in 2013, and he has doubled up on the nearest competition. The next closest pitchers to him all have four (Jorge De La Rosa, Cole Hamels, Jeff Locke, Mark Buehrle, Aaron Loup), and they are notably all left-handed.
How has he done it?
Primarily on the strength of what we called the ‘balk move’ for a right-hander. The name becomes clear when you concentrate on the legs of the pitcher.
When trying to get a read, the baserunner generally looks at the feet of the pitcher. Once the pitcher’s front foot goes, the runner is free to break for second or take his secondary lead, but if it’s the rear foot that moves first, the pitcher’s probably throwing over.
What’s confusing with Teheran’s move is subtle buckle of his lead knee almost simultaneously with the jab step with his back foot off the rubber. The movement from the front knee fools both the runner and the eyes of the umpire.
It’s an extremely effective move if done correctly, but not many have the quick feet and coordination to do it consistently without getting called on it. Teheran does, apparently, as he has yet to be called for a balk this year.