That's Starlin Castro driving a baseball out to the deepest part of a very deep left-center field in Pittsburgh, an impressive display of power that has become an increasingly unsurprising sight from the young Cubs shortstop. Through 72 games this year Castro is triple-slashing a huge (for a shortstop) .287/.331/.484, bouncing back from a horrific 2013 campaign better than anyone could have hoped for. Castro is on pace for roughly 25 home runs, something no Cubs shortstop outside of Ernie Banks has ever done. (Mr. Cub topped that mark an incredible seven times)

While I don't think he's going to knock 25 balls out of the park this season, I do think we're watching a different Starlin Castro than we have in the past. One with a definitive plan at the plate and an improved eye to help him carry out that plan. Get those laughs out of your system now, folks, ‘cause it's time to praise Starlin Castro's approach at the plate.

Really.

In years past, Starlin’s been known as a bit of a junkball hitter. He was the type of hitter who would put his bat on everything, mostly looking to smack the ball up the middle and to the opposite field. Coming into 2014, Starlin pulled just 34.2% of the balls he put in play, including home runs (37.8% were up the middle, and 28.1% were to right field). Furthermore, as you can see in the table below, Starlin was becoming increasingly comfortable with just slapping the ball the other way.

In 2014, though, Starlin is pulling the ball at a 42.4% clip, which represents a 24% increase over his career rate and a 31% increase over his 2013 rate. This change does not appear to be a fluke, either.

There’s a few reasons why Starlin’s been pulling the ball more often. For one, he’s clearly swinging at more inside pitches in what I assume is an attempt to get his bat head out in front and drive the ball to left field. Take a look at these heat maps from BrooksBaseball

[2010-2013]

[2014]

To compare one to the other, I’ve put together this heat map plot below. Positive numbers represent an increase in swings in that part of the zone in 2014 over his 2010-2013 mark, negative numbers represent Starlin laying off more pitches in that part of the zone. (For example, the 18.6% mark means that Starlin is swinging at pitches in that part of the zone 18.6% more often than in the past)

That is a huge increase in swings on pitches that are generally “inside”. These are pitches that Starlin can really turn on and drive to left field, and he has done exactly that – his line drive percentage on inside-middle pitches (those he’s swinging at 18.6% more often this season) is a whopping 44%.

Of course, getting pull-happy isn’t necessarily a great thing long term (anyone who watched Alfonso Soriano in Chicago can tell you that). If a player gets too pull-happy, he’ll often start rolling over a bunch of bad pitches on the outer third. One way to avoid this is to simply not swing at such pitches.

If you take a look at that embedded heat map again you’ll notice that, in addition to swinging at more pitches on the inner third, Starlin is also swinging far less often at pitches low and away. These are the types of pitches Starlin (and most hitters) pound into the dirt.

By laying off these pitches, Starlin’s doing a few things: he’s clearly waiting for inside pitches he can drive, he’s reducing bad contact and whiffs, and he’s working himself into hitter’s counts. The numbers bear this out, too – Starlin’s chase% of 29.8% is by far the lowest of his career, and he’s getting into more 2-0 and 3-0 (16.8% and 5.8%, respectively) counts than he has in the past (14% and 4.5%, respectively).

So what does a hitter do when he works himself into good counts, avoids bad contact, and looks to pull the baseball? He mashes baseballs, that's what.

On balls he has pulled this season, Starlin Castro is posting an obscene .800 slugging percentage with 9 home runs and a .390 batting average. Starlin has always hit for more power when he's pulled the ball (career .182 ISO to left, .147 ISO to center, and .131 ISO to right), but the .410 ISO he's putting up right now blows that out of the water. Castro's line drive percentage to his pull-side is 21% this season (up from 14.9% pre-2014), and his home run per fly ball rate to his pull-side is an enormous 64.3% (up from 19% pre-2014).

If he were putting up such ridiculous numbers without a clear improvement in his approach, I'd be worried that he'd be in-line for some seriously hardcore regression over the rest of 2014. However, given that he is working himself into ideal hitter's counts and looking to drive inside pitches, I have hope that Starlin can keep this up.

The pull-side home run rate is unsustainable (no hitter has maintained a rate above 60% over multiple seasons), but to what degree is up for debate. If Starlin really is capable of laying off pitcher's pitches low and away and working himself into favorable counts, he may be able to "cheat" and take max-effort swings at fastballs inside. In the video at the top of this post, you can see such a swing on an inside pitch in a 2-1 count.

He gets a pitch about thigh-high on the inner half of the plate, and takes a huge home run cut at it - he clears his hips early and takes a swing with a significantly steeper plane than we're used to seeing from him. If he is setting himself up to take such swings in appropriate counts, I could see him maintaining a pull-side HR/FB% well above his career mark of 19%.

Even if Castro's pull-side HR/FB% does come crashing all the way back down, he's still hitting more line drives to the pull-side than he has in the past. If he keeps that up, his .330 BABIP to his pull-side should be relatively easy to maintain. A good amount of those liners should become doubles, helping him maintain an elevated ISO. At the end of the day, pulling the ball more often is going to result in more hard contact (as will laying off balls), and more hard contact is always a good thing.

Of course, pitchers are going to adjust to what Starlin Castro has done in the last few months. They're gonna bust him inside and hope that he keeps swinging at pitches in off the plate, or they're going to pound the outer side of the strike zone and force him to go back the other way. The Pirates did a great job of that this past weekend, getting Castro to jam himself on fastballs that ran in and off the plate, and freezing him multiple times on the outer third of the plate.

If Castro has really become a guy who can take pitches out of the zone and stick to a plan, though, he'll be able to counter-adjust. If his eye really has improved this much, he'll learn to lay off the way-inside stuff, and he'll still be able to work himself into counts where he can sit on a pitch to drive.

It's taken some time, but it finally looks like Starlin has developed the "selectively aggressive" approach that the front office preaches. He's laying off of junk, he's working the count, and looking for pitches to drive. If this is for real, the Cubs might just be looking at a shortstop who can flirt with an .800 OPS for years to come.

@TommyECook

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