Three Keys to Understanding Aaron Hicks

You’re forgiven if you don’t much care about Wednesday’s swap of Aaron Hicks for JR Murphy. Maybe you’re not a fan of the Twins or the Yankees. Maybe you’re not a fan of baseball at all, and you somehow wound up here by accident. Or maybe you are a fan of the Twins or the Yankees, but you recognize this as a trade featuring two players with less than 2 combined WAR over more than 1,200 plate appearances. Hicks has been probably the more hyped of the two, but Murphy is the younger of the two, and he seems like a backup. This isn’t on the level of Brad Miller and Nate Karns, and even that wasn’t on the level of something truly big.

These are the moves we have available to discuss, though, and if you want to speak generally, every professional baseball player has a compelling story. They’re all tremendously talented, and they’ve all dreamed of big-league success. If you want to speak specifically, Hicks is interesting, and I’d rate his level of interest above-average. He’s a former top prospect who’s trying to recover from initial struggles, and the most recent year saw him take a step forward. As far as this trade is concerned, it’s important to understand 2015 Aaron Hicks, and what follows are three keys to fully grasping the Hicks campaign. What he was in 2014, he wasn’t this summer.

1. More aggressive

The Twins didn’t want Hicks to be so passive. There’s nothing wrong with drawing walks, but Hicks didn’t seem to get himself ready to hit. This touches on the difference between passivity and discipline, and you can either go up looking for walks, or you can earn them. In this most recent year, Hicks did more to earn the walks he drew, by swinging more often and showing pitchers he wanted to put the ball in play. Hicks swung more often at the first pitch. He went out of the zone a little bit more, but the bigger change was he attempted many more swings at would-be strikes. And Hicks made himself a far better two-strike hitter, understanding how to protect. He lifted his two-strike slugging percentage by more than 100 points. This, I think, is also pretty striking:

• 2013: 10% called strikeouts (out of all plate appearances)
• 2014: 12%
• 2015: 3%

Compared to 2014, Hicks just batted 166 more times, but he struck out looking less than half as much. Meanwhile, his swinging strikeouts barely moved. Hicks was more ready to attack, and so Hicks more resembled an actual big-league hitter.

2. Swing adjustments

To be honest, point no. 1 ties into this. Hicks is a switch-hitter, and he made some changes that then had various effects. The changes made him feel more ready to hit, so that’s where the increased aggressiveness came from, and you also see differences in trajectory. Brandon Warne has your backstory. For images, here’s Hicks batting righty in 2014:

Hicks batting righty in 2015:

Hicks batting lefty in 2014:

Hicks batting lefty in 2015:

There are some little differences in the hands, but the biggest and most obvious thing is the new, aggressive leg kick, replacing a toe-tap, or a heel-lift, whatever you want to call it. Hicks more or less stumbled upon the leg kick last offseason, and he kept it in spring training with the coaching staff’s approval. It’s a timing mechanism, and a lot of players go through a leg-kick phase, but with Hicks there’s at least evidence it did something for him. He’s always had a better right-handed swing; he struggled from the left side, which is unfortunately the more common side. Hicks wasn’t great from the left side in 2015, but he was a good deal better, swinging more readily and not so often cutting himself off with a slap attempt. While Hicks didn’t meaningfully improve his rates of making contact, I think it says something that the contact didn’t suffer while the aggressiveness went up.

Let’s establish some context for Hicks’ statistical changes. Between the last two years, Hicks came to strike out less often, and put the ball on the ground less often. Between those years, 272 players batted at least 200 times in each season. Hicks had the second-biggest decrease in groundball rate. He also had the fifth-biggest decrease in strikeout rate. These are big moves, and good ones for a fast hitter who also has a decent amount of power.

Hicks wasn’t as much of a groundball hitter in 2013. That was more of a 2014 development. In 2015, he un-did the grounders, but he also chopped what had twice been an elevated rate of strikeouts. So he improved on a 2014 problem and on a 2013 + 2014 problem. Not coincidentally, Hicks’ wRC+ while batting left-handed went 54 – 54 – 80. 80 is barely playable as a regular, Hicks making it okay with his speed and defense. But what this suggests is there’s still more room to grow. And now Hicks is going to Yankee Stadium.

3. Increased quality of competition

This isn’t really about Hicks’ skillset — we already know what that is. This is more to underscore the magnitude of his development between the last two years. Look at Hicks’ player page, and you might notice something: the average fastball he saw last year was 92.4 miles per hour. The year before, 90.7.

That doesn’t confirm anything, but it hints at something, something the rest of the numbers bear out. Two years ago, Hicks’ average opponent had a 114 ERA-. Last year, his average opponent had a 97 ERA-. The difference gets slimmer if you look instead at FIP-, but you’re still looking at a drop from 104 to 98. If you like OPS+, from Baseball-Reference, then two years ago his opponents averaged 104, and this year they averaged 95. However you look at it, there’s the same message: in 2015, Hicks faced stronger opponents than he did in 2014. They were quite a big stronger, and still Hicks developed as he did. I don’t know what this says about him going forward; maybe it just makes 2014 look all the worse. But it effectively makes his improvement bigger. Which means there could be still more improvement.

The biggest thing about Aaron Hicks is that, today, literally today, he was available for a player like JR Murphy. That tells you something about his market appeal, and odds are probably better that next year Hicks is below-average instead of above-average. Even if that’s unfair, Hicks doesn’t appear to be a blossoming star. What he did just do, though, is improve, and seemingly by quite a bit. A capable center fielder got better at the plate, and he’s somewhat newly 26 years old. You can’t blame the Yankees front office if it’s congratulating itself. You don’t have to dig deep to find stuff to like.