WHIP is a silly thing. Some people like to refer to it as a newfangled Moneyball stat, alongside VORP and tRA. But WHIP is old-fashioned, and not particularly indicative of player skill. Of course, pitchers who don’t walk anyone and don’t give up hits tend to be better pitchers, but we don’t need WHIP to tell us how good these pitchers are. WHIP is a byproduct of many other stats, and therefore should essentially be ignored when assessing pitchers.
That’s right: ignore WHIP. Because if you draft good pitchers, they are almost certainly going to have good WHIPs. In fact, there are very few pitchers whose WHIPs differ dramatically from their ERA and strikeout ability. And often times, when there is a significant difference between WHIP and other statistics, it’s a fluke, and unlikely to be repeated the next season.
It follows that pitchers with low ERAs tend to have lower WHIPs as well. Pitchers who have low ERAs tend to either get a lot of strikeouts or a lot of ground balls – or, failing this, they at least drastically limit their walks. Having a good WHIP is a byproduct of these three other skills: avoiding balls, missing bats, and inducing grounders. If you look for pitchers with these skills, their WHIP will follow.
The only exception for this is the mid-season tweak rule. Somewhere around July 1 (there’s no exact date, but the later the better), all bets are off: you need to tweak your roster accordingly, and most of what you read before the season can be thrown out the window. If there is one pitcher who has a particularly good WHIP and your WHIP is very high, there is nothing wrong with trying to obtain that pitcher – just be careful that the WHIP is for real, and not the byproduct of unsustainable luck.
In general, though, if you acquire a pitcher who avoids walks, gets strikeouts and induces grounders, that pitcher will have a more than respectable WHIP as well. And you won’t even have to look at that category.