Between 2013 – 2015, Adrian Gonzalez slugged .474. So far this year, Gonzalez has slugged .382. What’s going on? This one’s easy. Three years ago, Gonzalez didn’t hit many grounders. He ranked in baseball’s bottom fourth. Two years ago, Gonzalez didn’t hit many grounders. He ranked in baseball’s bottom fourth. One year ago, Gonzalez didn’t hit many grounders. He ranked in baseball’s bottom fourth. This year, Gonzalez has hit too many grounders. He ranks in baseball’s upper fifth. You don’t hit for power when you’re hitting these grounders.

Of course, that doesn’t so much answer the question as simply rephrase it. Instead of wondering where the power went, now it’s a matter of wondering where the grounders are coming from. This one also seems easy. Gonzalez’s back has hurt. Ever hurt your back? Makes it hard to do things. Makes it hard to get out of bed, nevermind slug a 95 mile-per-hour fastball. Not that all back injuries are alike, but Gonzalez has talked about this one. It makes all the sense in the world that his numbers would be worse because he’s physically compromised. To his credit, he still hasn’t been an offensive zero. But it’s fair to wonder if we’re going to see normal Gonzalez at all.

I wouldn’t go so far as to say the Dodgers are relying on him, not given as much talent as the Dodgers possess, but the team hasn’t yet totally clicked, and they’re one of five clubs slugging under .390. Pretty clearly, if Gonzalez were better, the Dodgers would be better, so they’re greatly invested in seeing him turn it around. There actually has been some progress, lately. It’s just that Gonzalez has some distance yet to go, and there are no assurances he’ll find his familiar baseline.

With the help of Baseball Savant, we can dive into Statcast. Typically, people will focus on exit velocity, or batted-ball speed. There’s also valuable information in launch angle. Ground-ball rate already works as a proxy, but anyway: There are 305 players who have had at least 50 batted balls tracked by Statcast in each of the last two seasons. Gonzalez has seen the sixth-biggest drop in average launch angle. This tells you the same thing the grounder rate does, but it does it in 21st-century style. Let’s hear it for Statcast!

Recently, there’s been some movement. Which, on its own, would be encouraging. I’ve plotted Gonzalez’s Statcast averages, over rolling 50-batted-ball samples. This goes back to the start of last year. Here are rolling launch angles and batted-ball speeds:

Look at launch angle first. Gonzalez really bottomed out not long ago, right around zero degrees in the middle of May. That’s slap-hitter territory, and not at all where Gonzalez would want to find himself. Since then, it’s been a steady climb, and while Gonzalez isn’t quite back to where he’s usually been, batted balls are returning to the air. Based on launch angle alone, it would look like Gonzalez is getting healthy. And it just so happens that, in the middle of May, Gonzalez took a few days and received treatment for his back pain. Pulling from the article linked above:

When Adrian Gonzalez returned to the Dodgers’ lineup last weekend, he stepped on the field without any noticeable discomfort in his lower back for the first time this season. Days earlier, he had received an epidural to treat a pinched nerve. “Hopefully, that corrected the problem,” he said.

That’s all good, and Gonzalez doesn’t want to be a ground-ball hitter. But we do have to look at the batted-ball authority, too, and not just the trajectory. I plotted batted-ball speeds, but maybe it’s better to look at batted-ball speed on liners and flies. Those are what Gonzalez really wants to kill. I stayed simple and looked at just batted balls hit with a launch angle above 0.0. Last year, in average batted-ball speed, Gonzalez ranked in the 67th percentile. This year, through the middle of May, he was in the 76th percentile. Since then — since his return to the lineup — he’s ranked in the 28th percentile. That’s over a sample of 54 such batted balls.

I fully recognize the density of that paragraph, so to try to just use words instead: Since Gonzalez took a few days off, he’s gotten back to hitting baseballs in the air, but he hasn’t been hitting them very hard. He did just recently generate his hardest-hit batted ball of the season, but that was just one event. The numbers make it look like he’s still compromised. He’s made some kind of tweak to try to elevate, but without the usual authority, homers are more likely to go for doubles and outs. Gonzalez has never had Giancarlo Stanton’s strength. He’s never been blessed with a ton of strength to give. It’s noticeable when he’s below 100%, and he still doesn’t seem quite right.

We’re coming up on the end of June. Which means we’re coming up on the All-Star Game, which means we’re coming up on the trade deadline, which means we’re coming up on the stretch run, which means the small-sample numbers aren’t such small samples anymore. Somewhere around here, it stops being early, so patterns become tougher to dismiss. Adrian Gonzalez’s missing power has become tougher to dismiss. The most probable explanation is that his back is just preventing him from swinging like he’d consistently like. If so, it’s good to know the reason, but knowledge isn’t its own solution. The back could remain an issue. It could flare up, without notice. I don’t know exactly what the feeling is within the Dodgers’ medical staff, so perhaps they have their own ideas, but this might just be the 2016 Adrian Gonzalez. It’s certainly what he’s been up to now, and now is June 21.