Mauer attended the same high school as Baseball Hall of Famer and former Milwaukee Brewer Paul Molitor who later became his major league manager with the Twins. Molitor has said that Mauer "has the best swing he had ever seen". Jim O'Neill, Mauer's baseball coach at Cretin-Derham Hall, said his former student "has been groomed for this job since he was a little boy. Mauer's dad, Jake, created a contraption for Joe he later named the 'Quickswing. ' The device dropped balls down a tube from eye level and released them at waist level. " Mauer had been asked to leave his T-ball league at the age of four, because he was hitting the ball too hard for the other players. "Another guy that came from Cretin-Derham Hall, Paul Molitor, was very similar, [and] had a good short swing," O'Neill said. "And they're both able to wait on the ball so long because they don't have the big swing. Like anything, you keep simple and keep it small or short, there's not a lot of holes in it and not a lot of room for errors. "