Joe Mauer was taking grounders at first base prior Monday at Target Field. It's a good idea, both in the short and long-term. The Twins won't have Justin Morneau back until sometime in August after neck surgery and Mauer needs to add some flexibility in order to prolong his career. While the 28-year-old has served as the designated hitter on occasion, he has never played another position besides catcher during his major league career.