Luis Arraez, Sui Generis

The 2019 Minnesota Twins hit, roughly speaking, all of the home runs. That’s not precisely accurate of course, but it’s close enough for government work; they set an all-time record for home runs. Of the 12 Twins who came to the plate 300 times in 2019, 11 hit 10 or more bombs. Bomba Squad isn’t just a nickname; it’s an accurate description of a team filled to the brim with home run hitters.

This article is about that 12th Twin. Luis Arraez had 366 plate appearances last year. He hit just four home runs. That was the sixth-lowest home run total among players with 350 or more PA, and the names below him aren’t inspiring; Billy Hamilton, Tony Wolters, Yolmer Sánchez, Nicky Lopez, and Dee Gordon weren’t exactly offensive powerhouses.

All told, only 29 batters hit less than 10 home runs in 350 or more plate appearances. That reflects the democratization of home runs, but it also means that it’s difficult to contribute offensively without dingers. In fact, 27 of those 29 players had a wRC+ below 100. The only two exceptions? Nick Markakis, who squeaked over the finish line with nine bombs and a 102 wRC+ — and Arraez, who batted .334/.399/.439 on his way to a scintillating 125 wRC+.

It’s not weird, not even a little bit, that players who don’t hit home runs are generally bad at offense. There’s no single outcome as helpful to a team’s cause as a home run. If you had to predict a player’s offensive output and you could only have access to one outcome type, you’d pick home runs, right? Walks might be okay, and doubles might be as well, but singles? Triples? Heck, throw in BABIP and strikeouts if you want. Nothing comes close to home runs.

Take a look at the correlation between the rate of each outcome and wRC+, the best measure of a batter’s overall production:

Again, it’s hardly surprising. Home runs always create a run. Weighted runs created plus, as you might imagine, measures a player’s ability to create runs. It’s not rocket science. It’s also not an artifact of the rabbit ball era. Home runs might be more prevalent in 2019 than they were in, say, 2007, but they’ve always been important. Here are those same correlations in 2007, a year when there were 1,819 fewer home runs than in 2019:

Sure, home runs were less important. But they were still the most important single outcome, and even more important than BABIP.

What does all of this mean? It means that if you want a shorthand for how good of a hitter someone is, you can simply look at their rate of home runs per plate appearance. The r-squared of home run rate to wRC+ is roughly 0.5, which means, speaking loosely, that half the variation in wRC+ can be explained by home run rate. Do note that I’m speaking loosely here; that’s not exactly what it means, but it’s close enough for a plain English explanation.

Of course, if you simply look at home run rate to pick out good hitters, you’ll miss some things. You’d think Mitch Garver was the best hitter in the majors, and that Gary Sánchez and Mike Trout were roughly equally as good last year. And you’d miss Luis Arraez:

There’s nothing particularly meaningful about this list. Some of the best hitters in baseball appear on it, but that’s because they’re good at everything and we’re only looking at one thing. Of course this method underestimates Trout; it treats everything except home runs as equal across all players, and Trout isn’t equal. He walks a ton, strikes out rarely, and hits the everloving snot out of the ball even when he doesn’t hit it over the wall.

All of these batters do something anomalous. Maybe they’re BABIP gods like Reynolds or Moncada. Maybe they have otherworldly plate discipline like Bregman or Rendon. Or maybe they’re Trout.

Arraez fits this bill. The lack of home runs is a huge hindrance to his game, but every other skill was off the charts in 2019. He was the worst hitter of this group of 15 because his lack of dingers was critical. But that doesn’t stop him from exceeding his home-run-predicted production by the most, because the walks, strikeouts, and BABIP all played.

Jake Mailhot looked into Arraez’s batted balls last year and noted his tremendous production on flares and burners. To wit, he had a top-30 rate of flares/burners in 2019, and he turned those balls in play into a .650 wOBA, 30 points better than league average.

A lot of that comes down to his league-leading 29.4% line drive rate. Everything Arraez hit was a low line drive, more or less. Batters have limited control over their line drive rates, so Arraez probably won’t duplicate this feat again in 2020, but the line drives aren’t the only thing going his way. His plate discipline also gives him a huge head start on his offensive production.

Walking more than you strike out isn’t really something that happens in baseball anymore. Pitchers today are Mario after eating a flower; they spit fireballs left and right, and you’re bound to get burned eventually. Arraez, however, was immune to their power. He drew a walk or was hit by a pitch in 9.9% of his plate appearances while striking out in merely 7.9%. As a result, he put the ball in play a ton, and balls in play are more valuable, on average, than the result of a random plate appearance.

Put it all together, and Arraez could have produced a .311 wOBA on contact and gotten to a league-average .320 wOBA overall. Given that the average batted ball went for a .384 wOBA in 2019, it’s not particularly hard for him to be an average hitter. In fact, only three players (Bregman, Kendrys Morales, and Rizzo) could do worse on contact and still be average at the plate. How bad is a .311 wOBA on contact? It looks like Austin Hedges or Orlando Arcia’s 2019 production; it’s no struggle to beat it.

In 2019, he easily bested that number. He produced a .359 wOBA when he made contact, which was below average — no home runs and all. But it was still far better than his breakeven point. And in 2020, he projects to do the same again; if you plug in his Depth Chart projections, he’ll need a .312 wOBA on contact to be an average hitter. And again, he projects to handily beat that with a .331 mark.

Indeed, Arraez’s is again forecasted to outperform his home run rate, this time by 34 points of wRC+. He’s not projected to hit more home runs, and it would be a shock if he did; he’s never hit more than four in a season. But he’ll likely do everything else right; he’ll walk a lot, rarely whiff, and dink bloopers and soft liners for singles and doubles all day. By home runs, Arraez should again look like one of the worst hitters in baseball. In every other way, he should again look like one of the best.