Consider if Santana became league average for AL shortstops the last 5 seasons in BB%(6%) and K% (slightly less than 17%). He would be striking out less, but walking more. In a 400 AB season, it would result in about 16 more balls in play. That would not be enough to offset regression. On the other hand, if his 2013 AA season was indicative of what Santana could do, BA .297, K% 16, BB% 4.1 his BABIP was .353 Less strikouts, but also less walks. Thus it ofsets regression of his BABIP if while stiking out less, he also gets less bases on balls