Mauer is also on pace for the most doubles in a year in his career, and the 2nd most home runs in a season for his career this year as well. He has the third highest slugging percentage of his career this year and the 2nd highest OPS+ of his career this year. I'm not really worried, if anything he might be trying to hit for a little more power this year, which is something people have been whining about for years it seems like. I think the "low walks" is an indication of the fact that he is NEVER hitting with runners in scoring position or even runners on that much, this means that teams really have no reason to pitch around him or get cute. In 26 games in May he struck out 31 times, which I am quite confident is a true career high, however in May he also put up a .371/.455/.571 line. So with all that said, I'm not really concerned at all considering Mauer is aruguably having the 2nd best season of his career, and he is doing it with one of the "worst" protection around him since arriving in Minnesota. Just imagine what he could be putting up if he is surrounded by Buxton, Sano, Hicks, Arcia in a couple years....