I don't know exactly what makes him a good hitting coach. (what makes a good hitting coach and how much does a hitting coach impact a player performance?) What I do know is this.
Several Cardinals have worked out with Mark in California over the last several Off seasons. Including Skip Schumaker and Ryan ludwick (Matt Holiday also worked out with him last off season and changed his swing but he wasn't as effective in Oakland with his new swing so mid season he went make to his old swing). I also know that almost all the cardinals spent some time in the cage with him during the winter warm up (not required). So apparently they were excited to learn somethings about hitting from him, and not wait until spring training. I have heard (can't find a source right now) that mark changed his swing during his playing career to make his swing longer, and as someone who has changed his swing he probably can help players make tweaks and improvements to their own swings (and understands the frustrations associated with making these changes). I also thinK I remember someone saying Mark was very good at breaking down pitchers and knowing tendencies. One of the key skills a hitting coach needs. If you know what a pitcher is going to throw you it makes it a lot easier to hit it. I also know Hal McRae appeared to be pretty horrendous as a hitting coach so he can't be any worse than that right?
