As we know, the regression expected of Santana is because of his BABIP over .400. Historically, that's impossible to sustain. But people with his skill set are likely to have a BABIP over league average. ZiPS projects his BABIP this year at .341, which is still very good. Mauer is a fantastic hitter and his career BABIP is about 10 points below that. So it's not like saying he'll regress is such a bad thing, it's just saying a .405 BABIP is through the roof amazing and not sustainable. His .353 OBP was hugely affected by that. As his BABIP drops down, he's going to need to walk more to keep his OBP up. Hall of Famer Rod Carew had a career BABIP a hair under .360. Still 45 points lower than Santana's 2014 BABIP. Yet his career OBP was in the .390s (40 points higher than Santana's).