Usually, these things tend to go in one direction. We talk about a player who seems underrated, and then, in time, that player becomes rated more or less appropriately. We’ve seen this happen with, say, Jose Quintana, who used to be considered a nobody even while he was pitching out of his mind. A lot more people now know how good Kyle Seager is. People know how good Starling Marte is. People have even figured out how good Kevin Kiermaier is, basically. Obligatory Ben Zobrist mention. Great players don’t stay hidden too long. I should note that I’m open to the argument Mike Trout remains underrated, but that’s different, because his ability is impossible for humans to understand.

You don’t see many players go from underrated to understood to underrated again. Such a sequence ordinarily wouldn’t make any sense. Yet, sometimes, there are just atypical circumstances. Of course there’s no infallible metric for underratedness. I know that I can’t prove anything, so we can get that out of the way up front. But I’m just here to remind you about A.J. Pollock. Pollock was once criminally underrated, and then, as time passed, he was recognized as one of the greats. Then he missed almost an entire baseball season. Out of sight, out of mind — that is how we work. So Pollock is back to where he was, preparing for camp as Arizona’s neglected star.

There’s a lot of uncertainty surrounding Andrew McCutchen, which is among the primary reasons he hasn’t been traded. McCutchen is right around 30 years old, and two seasons ago, he was a six-win outfielder. Then he dropped to being a half-win outfielder. Uncertainty exists because McCutchen was a below-average player over 153 games.

Pollock is right around 30 years old, although he’s a year younger than McCutchen is. Two seasons ago, he was a six-win outfielder, and then he dropped to being a half-win outfielder. But where McCutchen was worth almost nothing over 675 trips to the plate, Pollock was worth almost nothing over 46. By now, you probably remember seeing clips of him fracturing his elbow while sliding early last year. Pollock isn’t a bounceback candidate in the way McCutchen is. We haven’t actually seen A.J. Pollock be bad.

It’s not particularly good to miss a season. We’d all be more comfortable if Pollock were just a healthy Pollock all of the time. But the injury Pollock sustained shouldn’t have a lasting impact, beyond the 2016 season it helped to tank. In a similar vein, maybe you’d want an article like this to be written about Michael Brantley, who was a six-win outfielder in 2014. Brantley, though, has had major shoulder problems, and it’s far from guaranteed he’ll ever get his old swing back. We can’t know what we’ll get from any player, yet Pollock feels safer than Brantley, and he feels safer than McCutchen, too.

I don’t have a good reason for the timing of this post. A.J. Pollock hasn’t been in the news more than usual. Even with his return, I don’t expect the Diamondbacks to make a push for the playoffs. It’s just — do you remember how good Pollock has been? This is a reminder, showing Pollock’s percentile rankings out of all players with at least 1,000 plate appearances since 2013. Note that playing that often over the past four years already selects for talent. So.

Pick a skill, and Pollock has been better than average at it. Running the bases? He’s been awesome. Playing center field? He’s been awesome. Knowing the zone? He’s been fine. Making contact? He’s been great. Hitting for power? He’s gotten only better and better. We’ll come back to that, but as far as all this goes, Pollock is one of those across-the-board contributors, kind of similar to Mookie Betts. So by WAR/600, we get Pollock at 5.5. For reference, Betts is at 5.4, and Manny Machado is at 5.3. Miguel Cabrera’s at 5.2. When he’s been on the field, Pollock has been more valuable than almost anybody. It’s just been a while since he could play every day. He’s back, now, and he’s 100%.

It’s easy to have forgotten, or just not known, that Pollock is another one of those swing-change guys. This gets into that power development I referred to earlier, as Pollock was never expected to become so good. Pollock debuted in the majors in 2012, and this is what his swing looked like:

A year later, you can see that Pollock added the familiar leg kick:

And here’s a 2014 swing. It looks similar to the 2013 swing, only with a lowering of the hands. This swing has stuck with him ever since, and he’s pushed ISOs close to .200.

Just to keep up the .gif barrage, here’s a glimpse of what Pollock looked like in the most recent season, since 2014 was a while ago.

Do the swing and follow-through ring any bells?

Josh Donaldson’s swing is more visually aggressive — Donaldson looks more like he wants to actually hurt someone. He raises his knee up higher. But you get a similar leg kick, you get a similar coil, and you get similar activity in the bat. Pollock hasn’t figured out how to lift the ball quite like Donaldson has, but these are two of the premier swing-change guys from the last few years, and this side-by-side isn’t coincidental.

A.J. Pollock is 29, which is too young to be aging. Although he just missed basically a whole year, he missed time with the sort of injury that shouldn’t hold him back anymore, now that it’s healed. The last we saw Pollock, he was one of the game’s better defenders at a premium position, and that should still be true. I can’t imagine he’s forgotten how to run the bases. And to go with his high contact rates, Pollock has learned how to more consistently drive the ball all over the place, just like so many of the other swing-changers on other rosters.

Because of the time missed, I’ll grant there is uncertainty. Yet I prefer the Pollock path over the McCutchen path, and as the Diamondbacks look to turn the page, Pollock is going to be absolutely critical to any 2017 chances they might go on to have. It’s not that you didn’t know A.J. Pollock is good. It’s just that it’s easy to forget about players when they don’t get to play. A.J. Pollock is again an active player, and all around, he’s one of the best at what he does. It was nice of other players to keep the leaderboards warm.