The Royals are playing chicken with batter projections

Some hitters should be doing better.

Predicting how a player is going to perform in the future is hard. Some guys get better out of nowhere thanks to an improved swing or a new pitch. Some guys get better because figuring stuff out in the big leagues takes some time. Some guys get better (or worse) because of off the field changes that you can’t forget. And then there’s aging, which comes for everyone but at different paces.

So what do you do? You use a combination of skill evaluation, past stats, and a heck of a lot of similar player data. Computerized methods of predicting future performance are called “projection systems,” such as STEAMER or ZiPS. These systems are largely better than humans because of objectivity and processing power, but they are often wrong about specific players because no method of predicting player performance is perfect.

And then there’s a more simple method of player production. For batters, there is a suite of “expected” stats. These expected stats look at batted ball data and try to give proper credit based on launch angle and exit velocity independent of the actual on field result.

This is relevant for the Royals because both projection systems and expected stats say that the Royals hitters should be doing way better than they are. In real life, that hasn’t been the case—the Royals have scored two or fewer runs in a frankly embarrassing 43% of their total games this season. So the Royals are faced with a decision: how long should they rely on the projections and expected stats before making changes? And should they?

Let’s start with projected stats, which is a little more straightforward. One of the best individual offensive stats is weighted on base average, or wOBA. Fangraphs describes wOBA as “a rate statistic which attempts to credit a hitter for the value of each outcome (single, double, etc) rather than treating all hits or times on base equally.” Meanwhile, xwOBA tells “the story of a player’s season based on quality of and amount of contact, not outcomes.”

In other words, wOBA is what happened, and xwOBA is a measure of what would have happened independent of defense or ballpark. And for the 13 Royals who have accumulated at least 50 plate appearances, the story is clear: everyone has been ridiculously unlucky.

Salvador Perez, in fact, has been the unluckiest hitter in baseball, the only one whose actual production runs under his expected production by triple digit points. In fact, only two out of the 13 Royals hitters in this set have been more fortunate than they should have been (I’m not counting Witt here since his figures line up so well).

Of course, the Royals still have had seven hitters put up an xwOBA below .300, which implies that the team should still be looking at replacing multiple hitters this year. Except not so fast! This is where the other wrinkle comes into play: what the projection system thinks each player should be producing at based on past data. Here, I compared xwOBA with what ZiPS thinks the player will produce at for the rest of the season.

Here, you can see that Perez’s batted ball outcomes are way better than what ZiPS thinks should be happening, which is nice. What is not nice is that eight players are underperforming their ZiPS projection, all of them by a pretty large margin.

What does this all mean, then? Well, it means that the Royals are holding pat and not making big moves on the offensive side of the team because the expected stats and projection systems are saying the same thing: that positive regression is incoming. We saw that recently with the wild seven home run performance in Baltimore. The Royals, by and large, are putting good swings together but have not been rewarded for this.

However, there is one warning signal that the Royals would be wise to heed. You’ll notice that MJ Melendez was both way under his expected stats and way under what ZiPS thought he’d produce. But the Royals made the right decision in sending him down to Triple-A: ultimately, it’s about what happens on the field, not on a spreadsheet. Sometimes, a player stops being a useful hitter before the math can catch up.

We are past that point with Hunter Renfroe, whose days of being a productive big leaguer are over. And though it pains me to say that, we are rapidly approaching a point where Michael Massey loses his starting gig or gets sent to the minors—frankly, that would have probably happened if the Royals had a replacement ready to go.

But beyond those two potential moves, the Royals are probably right to sit tight and hope the storm blows over. It sucks, and it’s no fun to watch, but baseball takes a long time to stabilize and that’s just how it is sometimes.