Just two years ago, Alex Wood was one of the best young hurlers in the game.

From the time he debuted in May of 2013 until the end of 2014, he ranked third in ERA among pitchers 25 and under, behind two guys you may have heard of: Chris Sale and Madison Bumgarner. They’re pretty good.

Among left-handers, regardless of age, he ranked fourth, behind Sale, Bumgarner, and another guy you may have heard of: Clayton Kershaw. He, too, is pretty good at this pitching thing.

Wood always had his doubters, who worried about his velocity, how his funky delivery would affect his health, and that batters would eventually figure out his delivery. Nevertheless, there’s no denying the amount of success he achieved during his first 250 big league innings.

Things started to go downhill for Wood in 2015. Though he was solid for a good stretch in the first half, posting a 2.78 ERA in 10 starts between May and June, his year-end numbers were markedly different from during his first 250 innings. Let’s look at the numbers:

Alex Wood Career Pitching Statistics

Alex Wood Career Pitching Statistics

What changed in 2015?

A New Jersey on His Back

Well, for one thing, the color of his uniform changed mid-season, when he was traded from the Braves to the Dodgers as part of a three team deal.

While his results were much better prior to the trade (3.54 ERA with the Braves, 4.35 with the Dodgers), his peripherals actually got better after the move west, as his xFIP fell from 4.02 pre-trade to 3.71 post-trade.

Pre-trade, he was the beneficiary of a 6.9% HR/FB ratio, which skyrocketed to a lofty 16.3% mark after the trade, despite the move to a better home run park.

It’s clear that Wood wasn’t the same pitcher in 2015 that he had been prior to it.

The key question when evaluating Wood, then, is what exactly happened to him in 2015, and whether he has or can make the necessary adjustments to get back to his prior level of success.

Looking at the table above, there’s a clear smoking gun when it comes to diagnosing the problem behind his 2015 struggles: his inability to miss bats, as evidenced by a drop off of nearly seven percentage points in K%, backed up by a 1.4 point drop in his whiff rate.

Looking at Brooks Baseball, we can see that the drop in whiffs is tied mostly to his changeup, which saw its swinging strike rate decrease from 20.07% in 2013 to 16.56% in 2014 all the way to 11.62% in 2015:
Alex Wood LA Dodgers Percentage of Whiffs
The contact rate against Wood’s changeup rose by more than five percentage points over 2014, which was itself nine points higher than in 2013.

All this despite throwing it in the strike zone nine percent less than in 2014.

These are not the kinds of trends you would hope to see from a promising young hurler like Wood.

What drove the loss of changeup whiffs?

For that, I believe there is a simple answer that can be spotted in the chart below:

Alex Wood LA Dodgers 2013-2015 Pitching Velocities

2013-2015 Pitching Velocities

While the gap between Wood’s fastball and his changeup stayed about the same (about seven miles per hour), his fastball velocity itself declined steadily.

As Harry Pavlidis showed, that’s a bad thing when it comes to getting whiffs on your changeup, even if the changeup also loses velocity proportionately.

So while the changeup itself didn’t change in a vacuum, it changed in the context of Wood’s arsenal.

Batters simply respected Wood’s fastball less, which led to more contact against his changeup.

So while the changeup may have been the culprit in terms of results, Wood’s fastball was at the root of his struggles.

When looking at changes in fastball velocity and effectiveness, it’s often necessary to delve into a pitcher’s mechanics, especially when they’re as strange as Wood’s.

If you haven’t seen Wood pitch, well, his delivery is quite an interesting sight:

Alex Wood Pitching Mechanics

Pitching Mechanics

That’s certainly a lot of “funk” in his delivery, and you can see why it’s so deceptive.

He hides the ball well (look how far behind his back the ball is), and he’s also hard to time due to that little bit of a hitch that happens right before he starts to bring the ball forward.

While Wood’s delivery is certainly fascinating by itself, what I want to talk about is not so much the inherent funk of it (which has remained constant over time), but rather something that hasn’t remained so constant: his arm slot.

Alex Wood and His Arm Slot

Let’s start with a graph of his vertical release points by month, courtesy of Brooks Baseball:

Alex Wood LA Dodgers Release Points

Release Points

There’s a lot of movement here.

I like to think of his arm slot as going through five distinct phases.

It started out high* when he made his debut in 2013 and remained that way through the first two months of 2014 (what I’ll call the “debut phase”).

After that, it declined throughout the remainder of 2014 (the “decline phase”).

In 2015 it was lower than ever before, and remained there throughout the season (the “sidearm phase”).

In 2016, prior to his disabled list (DL) stint it returned all the way back to debut phase levels (the “rebound phase”), but dropped back down when he returned from the DL and was sent to the bullpen.

*Well, relative to his release point at other points in time it was high, but even at it’s highest Wood was coming from a three-quarters slot. At the highest his monthly fastball release points have ever been (5.82 feet in 36 fastballs in March 2016) he was still releasing the ball approximately six inches lower than his standing height (6’4”). For comparison, teammate (and best pitcher on the planet) Clayton Kershaw is one inch shorter than Wood but with his overhand delivery releases the ball 6.7 inches higher, for a standing height-release point difference of +1.7 inches. Rich Hill, another teammate (one who uses more of a ¾ slot) releases the ball about 3.4 inches lower than his standing height. As you can see, even at it’s highest Wood’s arm slot is very low. Alex Wood Debut Arm Slot[/caption] It’s unclear what’s driven these arm slot changes: perhaps some of them were intentional, perhaps some were subconscious.

It is clear to see that there is a direct correlation between Wood’s arm slot and his results.

There are two questions, then:

First, did raising his arm slot back to where it was during his dominant “debut phase” fix the problems that ailed him during 2015 (his “sidearm phase”)?

And second, where will we see his arm slot in 2017?

To answer the first question, let’s begin with a zoomed-out look at his performance in 2016.

To do that, let’s bring back a table from earlier in this article, but with 2016 added in:

Alex Wood LA Dodgers Career Statistics Including 2016

Career Statistics Including 2016

If you looked just at the ERA column, you might conclude that Wood’s return to his previous arm slot was all for naught and that his performance did not improve in any meaningful way.

Taking a look at his peripheral numbers (which is a must when dealing with samples of only 60 innings), however tells a very different tale.

Our “smoking gun” from our analysis of his 2015 season, his strikeout rate, bounced back to a new career high of 25.9%, driven by a rebound in his swinging strike rate.

Meanwhile, his walk rate held steady.

Earlier on, we zeroed in on his fastball velocity as the root issue behind his strikeout rate decline.

Was he able to bring that back in 2016?

Sure enough:

Alex Wood LA Dodgers Release Point Fastball

Fastball Release Point

His fastball velocity returned to levels we hadn’t seen since his debut season.

How did that affect his changeup, which we saw was the primary victim of his loss of velocity?

Alex Wood LA Dodgers Changeup Percentage of Whiffs

Changeup Percentage of Whiffs


With his velocity back, Wood’s ability to miss bats with his changeup rebounded completely.

In addition to the return of his fastball velocity, Wood’s changeup also benefited from a different approach.

Wood threw his changeup on the first pitch less often in 2016 against batters of both hands: against right-handers he decreased his first pitch changeup rate to 13% after posting a 16% rate prior to 2016, and against left-handers he didn’t throw a single first pitch changeup in 2016, after doing so 4% of the time in the years prior.

He also decreased his rate of changeups when behind in the count to a left-handed hitter from 12% to 8%.

He made up for his lack of changeups early in counts with a marked increase in his willingness to turn to it when ahead in the count against right-handers, going from an 18% rate of changeups in such situations to a 24% rate, including a six point increase in changeups with two strikes against right-handers.

As you might guess, given the counts in which he was throwing his changeups, Wood threw the changeup in the zone substantially less often, with his Zone% on the changeup dropping from 37.0% prior to 2016 to 28.6% during the 2016 season, according to FanGraphs.

This change is interesting because his first-pitch changeups, actually found the zone more often than in the past (41% versus 27% zone rate on first-pitch changeups, according to Brooks Baseball), while his two-strike changeups found the zone almost never in 2016 (7.5% zone rate, versus 25.5% in the past).

This change in approach led to substantially less damage on the changeup (career low .067 ISO against), as well as more groundballs on it (career high 56.5% groundball rate).

So we’ve answered our first question…

Wood’s change back to his prior arm slot did cure what ailed him during the 2015 season. But what about our other question: where will we see his arm slot in 2017?

Alex Woods 2017 Arm Slot

To answer that question, let’s take a look at his first outing of the 2017 season, a two inning relief appearance against the Padres on April 5th.

Here’s his arm slot during that outing:

Alex Wood LA Dodgers Arm Slot

LA Dodgers Arm Slot

According to Brooks Baseball, his vertical release point on his sinker sat at 5.57 feet.

That’s about an inch lower than where we’ve seen it during Wood’s good stretches, but about 3.25 inches higher than during his miserable 2015 season.

His velocity during that outing sat at 93.84 miles per hour, though that’s obviously inflated by the shortened outing compared to pitching out of the rotation.

I am encouraged by the fact that his arm slot during this outing was far closer to the good version of Wood than the poor one.

So even though it is impossible to say at this point where Wood’s release point will sit during the 2017 season, my money is on a similar arm slot to what we saw in his 2013 debut and in his shortened 2016 run of success.

Up to this point, we’ve focused almost solely on Wood’s arm slot, fastball, and changeup.

And rightfully so.

Those are the key items that are most likely to determine his success or failure in 2017.

But we would be remiss if we didn’t discuss Wood’s primary out pitch: his curveball (especially considering it is a pitch that didn’t exactly remain static).

Wood’s curve saw a career high in whiffs in 2016, at 17.9%.

Strangely enough, that came with less movement than early in his career.

His curveball has lost horizontal break each season and in 2015 it lost over three inches of drop, which remained the case in 2016.

How did Wood manage to get more whiffs with less movement?

The answer is by transitioning it to a sharper, more powerful curve.

While his fastball was losing velocity in 2015, his curveball was gaining velocity, substantially narrowing the gap:

Alex Wood Pitching Velocity

Alex Wood Pitching Velocity

In addition to velocity, Wood’s curveball also gained spin from 2015 to 2016 (the first two years for which we have spin rate data available, going from 1775 RPM to 1925 RPM).

This gives him sharper action on the curve.

In an incredibly small sample so far in 2017 (only six curveballs), he’s increased his spin rate even farther, all the way to 2203 RPM.

If even part of that increase is sustainable, Wood’s already dominant curveball could be taking yet another step forward in terms of sharpness.

With Rich Hill, the Dodgers’ other side-winding lefty with a deadly curve, hitting the DL due to a blister,

Wood is slated to make his return to the rotation, but if he can continue to combine a return to the arm slot and velocity he utilized to first become successful with an even better curveball, Alex Wood could have quite the season ahead of him.

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