According to ESPN.com, and to this blogger, the answer is clearly Atlanta Braves pitching coach, Leo Mazzone.
He's got my vote as the first assistant coach to be in the Hall of Fame.
Sabernomics (the Freakonomics of baseball) has even calculated a Mazzone Effect documenting his impact on pitchers such as Jaret Wright, who should give Leo at least 1/2 of the Free Agent contract he signed last fall.
As the Braves move closer to winning their Division (for the 15th straight year!), I think it's time they put a rocking chair in the dugout, so Leo can do his signature rocking backing and forth in comfort.
P.S. Bloggers tend to get caught up in their own self-importance and dramatically announce they are taking a break, or go on and on about how they're sorry they have "neglected" their blog.
Well, you may have noticed I haven't blogged lately, so yada, yada, yada... (insert your own witty and/or sensitive remark here).