Mauer holds the MLB single-season records for the highest single-season batting average for catchers (.365), which he set in 2009[78] and the highest single-season on-base percentage for a catcher (.444), which he also set in 2009. His career on-base percentage is the highest among major league catchers with a minimum of 500 games played.[79] Mauer is also the first AL catcher to win a batting title[80] and holds the record for the most batting titles by a catcher in a career (3 times).
Overrated I guess to hold 3 career catching records. If anything he was underrated. Its no conicidence that the Twins pitching staffs declined when he was no longer able to catch as he was one of the best game callers and defensive catchers as well. Was a joy watching him with a bat in his hands as well as calling and catching games. He deserves to be a first ballot hall of famer.