A Note on How Walks Have Been Removed from SCOUT
For this edition — and, perhaps, for future editions — of the SCOUT batting leaderboard, I’ve removed walk rate. Speaking anecdotally, there seems to be a significant-enough population of hitters who’re able to post high-ish walk rates against minor-league (and, presumably, spring-training) pitching based largely on selectivity, but whose walk rates decline considerably when they face more talented major-league pitchers. Dan Szymborski, proprietor of the ZiPS projection system, has confirmed that high minor-league walk rates do not necessarily beget high major-league ones.
A Note on What Might Else Inform Major-League Walk Rates
Probably power. Hitters with power definitely walk more than those who lack it (i.e. power). See the graph below, for example.
However, in the comments of the article, a reader says the opposite, that minor league BB% correlate best with major league wRC+