Jean Segura’s swing changes allowed him to become a complete hitter

“Few harbor any real expectations for Segura anymore.”

That was the first sentence under Jean Segura’s player profile in the 2016 Baseball Prospectus Annual. And with good reason. After a breakout 2013 — his first full season in the majors — in which he slashed .294/.329/.423 on his way to 5.6 WARP, Segura’s performance had gone in the tank.

Over the next two seasons, his combined slash line was .252/.285/.331 — just a 65 wRC+, and as my colleague Luis Torres correctly pointed out in September, even 2013 was mostly just a crazy-hot first half rather than a true full season of excellence.

Still, his on-field struggles paled in comparison to what was going on in his personal life. In July 2014, Segura’s 9-month-old son passed away in the Dominican Republic. It would be unfair to draw a direct correlation between Segura’s disappointing performance and that tragedy — he was not hitting well in the preceding months — but it may very well have exacerbated whatever was causing his performance at the plate to decline.

Needless to say, it was a very rough couple of years for Segura, both personally and professionally. As disappointing as it was to see that 2013 dynamo disappear so quickly, empathy made this a player everyone rooted for. We root for almost any struggling player to turn it around; for Segura that went double.

That’s why it was so great to see him not just recover in 2016, but have the best season of his career.

Segura was acquired by the Diamondbacks a year ago in what turned out to be perhaps the best move of the Dave Stewart era. Considering some of the other moves that regime made, that may undersell just how good Segura was last season. Playing primarily second base for the first time in his career, Segura was legitimately great. FanGraphs, Baseball-Reference, and Baseball Prospectus’ various WAR models all had him as one of the best 22 — at least — position players in baseball.

And while that shift to the keystone harmed his effectiveness with the glove, Segura’s bat was better than ever. Just look at the improvements across the board from 2015:

More walks, fewer strikeouts, and way more power. He was a completely different player.

What changed — besides the results — was identifiable early in the season. In April, Fox Sports’ Ken Rosenthal wrote about Segura’s swing changes for 2016. Namely, he had lowered his hands. In that piece, Segura was quoted as saying, “Now with my hands lower, I don’t have to go down and then go up to hit the ball. I go directly to the ball.” Let’s take a look at what he means by that.

First, let’s start at the beginning of Segura’s swing. Check out the difference from 2015 to 2016 in where his hands are once the opposing pitcher comes set, with 2015 on the left and 2016 on the right:

Different camera angles, obviously, but you can see a clear difference from 2015 to 2016. With the Brewers, his hands were starting up at his ears. With Arizona, they’re down by his rib cage.

Why this made such a big difference should be evident in these next screenshots. Look at where Segura’s hands are when he begins his swing:

His hands end up in the same spot, right around the letters, but it’s easy to see how much more motion was required to get to that spot in 2015. Here’s how the two swings look in real time:

You can see what he means about going directly to the ball. In 2015, he was wasting a lot of extra motion to begin his swing, which was preventing him from driving through the baseball. In 2016, that swing path was far more fluid, and as a result, he made better, harder contact.

Of course, the less motion in your swing, the more time you have to make a decision on whether to pull the trigger. That extra split second not only allowed Segura to hit for more power, it allowed him to thrive against essentially any pitch thrown his way.

In 2016, Segura was one of just 26 qualified players with a positive linear weighted value against fastballs, curveballs, sliders, and changeups. That put him in the company of guys like Mike Trout, Mookie Betts and Josh Donaldson.

Linear weights aren’t a perfect evaluation of a hitter’s ability to hit a certain pitch because they’re so dependent on sequencing, but it’s an impressive feat nonetheless.

Perhaps a simple table of batting average and slugging percentage against those pitch types over the last two seasons will better show how much better Segura was in 2016 at hitting those pitches:

With the small-sample exception of Segura’s 2015 performance against curveballs, he was much better against any pitch type he saw, and a definite sign of real progress.

Considering how good he was in 2013, I’m not sure Segura’s 2016 was a breakout season, per se. But factor in the swings changes, and how bad he was in 2014 and 2015, and I’m not sure what else to call it. If nobody expected you to be good and then you had a great season, that seems like the definition of a breakout.

Regardless of what you deem it, as it would be for any player coming off a big one-year jump in performance, the question is whether Segura can sustain the level of play we saw in 2016 in 2017. Is this the player he is now, or should we expect heavy regression?

The answer to a question like that should always be “somewhere in between.” Outside of Trout, Kershaw, and a select few other superstars, we shouldn’t expect anyone to be a five- or six-win player, as Segura was in 2016.

The various projection systems would agree with that answer. PECOTA (.251 TAv), ZiPS (95 OPS+) and Steamer (94 wRC+) all project him to be a little below-average as a hitter. That’s almost exactly halfway between where he was in 2015 as compared to 2016. No projection system can specifically account for a hitter’s swing change, so if you wanted to be a bit more bullish on that, it would be understandable.

2017 will bring the challenge of not just maintaining the level of performance, but of adjusting to another new environment, as Segura was traded once again in November, this time to the Seattle Mariners. In addition to changing addresses, he’ll also be moving back to shortstop to play alongside Robinson Cano.

Going from Chase Field to Safeco Field will surely hurt Segura’s counting stats a bit. Seattle is not a very good place to hit overall, though it allows more home runs than its reputation would lead you to believe.

That does not mean he’ll again become the almost unplayable hitter he was two seasons ago, however. As long as an offseason away doesn’t hinder Segura’s ability to maintain his new swing mechanics, this improvement should be sustainable, even if the results aren’t as good as they would have been in the desert.

The Mariners acquired him with the clear purpose of making the playoffs, after all. 2016 Jean Segura might well have put the team over the edge. Will the 2017 version?