I've been holding off on writing this article.  There have been some signs that something's off with Jake Arrieta.  I figured he would suddenly snap out of his funk, unfurl a complete game shutout and make me look silly in the process.  And he still might do just that.  But, I can't keep sitting idly by.  Something's wrong with Jake.  I don't mean to be alarming, but this just isn't right.  I have to write about this, much to my own chagrin.

To those who haven't been following the Cubs, this probably seems silly.  'Oh no, poor Cubs fans with their ace and his unsightly 2.33 ERA.  I wish we all had an ace that is being talked about as a possible All-Star Game starter.  However will you deal with a pitcher giving up multiple runs in consecutive games!?'

And, to be fair, we all probably have unrealistic expectations for Jake.  He spent the better part of a full calendar year carving up everyone in his path.  He shattered records that stood for decades.  It took him less than a dozen regular season starts to throw his first and second no-hitters.  The only way to beat him was to throw a no-hitter.  Literally.  The Cubs' only regular season loss in a 28-start span from Arrieta was when Cole Hamels no-hit them.  Arrieta won a Cy Young last year, and he recorded the lowest second-half ERA in major league history.

He's been fabulous as a Cub.  He's thoroughly dominated the league the last two years.  There aren't enough superlatives for me to describe how great he has been.  At some point in 2015, he transformed into God-mode Arrieta.  And his invincibility lasted so long that we all forgot that he was actually mortal.  It's still hard to believe, what with his resemblance to a Grecian god.  But now we remember.  Now he's losing games to guys that look like this:

  

 

Things haven't been so bad.  For the year, he ranks 8th in the majors in fWAR.  He ranks 4th in RA9-WAR.  Just a week ago, his ERA sat at 1.74.  Despite that Neil Walker home run last night, he still has the lowest HR/9 in the majors.  He's been really solid until the paroxysm we've seen this week. This didn't come out of nowhere, though.  Things have seemed off all year.  He's appeared to have been missing that je ne sais quoi.  This has been most evident in his walk rate.  His BB/9 is 3.49 this year, after being 1.89 last year and 2.36 the year before.  This is an issue that's been plaguing him all year: 

  

 

The stuff is still there, though.  Opponents are only hitting .187 against him, and they are only slugging .267.  He is still near impossible to hit.  He ranks in the top twelve in the majors in terms of lowest average exit velocity of pitchers with at least 150 batted ball events.  He's still got the same velocity on his pitches.

  

 

The movement on his stuff is the same -- both his vertical movement and his horizontal movement

 

  

 

So what's different?  Well, let's check out his PITCHf/x plate discipline profile at Fangraphs.  Hitters are actually making the exact same amount of contact against him this year as they were last year.  Their contact rates on his pitches both in and out of the zone are similar, too.  He's even throwing around the same amount of pitches in the strike zone.  46.4% of his pitches have been in the strike zone.  He was at 47.9% last year and 47.0% the year before.  His zone % is down a little, but not too significantly.  Where are the walks coming from, then?  Ah... his O-swing % (the percentage of his pitches outside of the strike zone that are swung at) is at 29.2% after being at 32.9% and 32.8% in the two previous seasons.  Hitters are laying off of his stuff out of the zone more often.  They are only swinging at 44.9% of his pitches overall, after swinging at 47% of his pitches last year.  Arrieta's talked about how hitters are approaching him differently.

The only thing is that he's wrong.  Hitters aren't approaching him differently.  This is all about Jake.  This is about his command absconding.  He originally became Jake Arrieta, the bearded demigod, because he discovered his command in Chicago.  Then, it vanished abruptly.  It's like in the movie Space Jam, when some intergalactic creatures arrive on Earth and steal Charles Barkley's and his fellow NBA superstars' athletic abilities.  It happened in the snap of a finger, out of nowhere.  You know how that movie goes.  Michael Jordan does some GOAT things, and then Bill Murray comes and saves the day. 

  

 

Well, that's where Jake is at right now.  Whereas Patrick Ewing forgot how to shoot, Jake forgot how to locate his pitches.  The problem we face now is that Bill Murray already made his appearance in this chronicle, and Jake still can't pitch. 

 

  

 

I'm going to present to you two strike zone plots from Brooks Baseball. 

 

 

  

 

That first one is from last night.  The second one if from Arrieta's no-hitter against the Dodgers last year, in which he struck out 12 guys and walked 1.  This was Arrieta at his most dominant, in the middle of his amazing second-half, mowing people down.  But... those two plots don't look all that different.  He was throwing the ball all over the place even during that magical night last year.  He got a few more swings (and misses) at pitches below the zone.  But, it's not like he painted the zone or anything.  That's the thing with Jake; he doesn't have to paint the zone.  Even last year, when he had the 14th-lowest BB/9 in the league, he only ranked 43rd in the league in terms of most pitches, on average, thrown in the strike zone.

We're going to break down those two strike zone plots from above to see why they are very different, despite their appearances.  Specifically what we are going to look at is his sinker usage.  Arrieta throws his sinker more often than any other pitch -- over 45% of the time.  It's also the pitch that he's had trouble commanding this year.  Here's what his sinker looks like, in gif form: 

 

 

He can do a number of things with that sinker.  He can start it off the plate against a right-handed hitter and bring it back across the plate for a called strike, like in the gif.  He can start it over the plate to a right-handed hitter and saw him off as it darts inside.  And against left-handed hitters, he likes to start it over the plate and then have it dart outside.  The next image will be the strike zone plot in that no-hitter, against left-handed hitters, with pitch types listed.  The following image will be the same plot, except for last night.  We're only concerned about the sinker right now, so pay attention to the gray squares. 

  

 

 

In the no-hitter, the sinker was doing exactly what he wanted it to against lefties.  He had them on a string.  They start off looking like strikes and then fall off outside the zone.  And they were nearly all zone high.  There is a distinguishable approach there.  They dot the outside of the zone, up and down the zone, with most of them just outside the zone.  Last night, the sinker was all over the place:  up and down, some in the zone.  Most of them outside the zone were way off the zone.  He also had a bunch that were over the plate but below the zone.

Now check out the strike zone plot against right-handed hitters.  Again, the first image will be from the no-hitter and the second from last night.  Again pay attention to the sinker. 

 

  

 

In the no-hitter, most of his sinkers were located in the zone to righties.  Last night, he had a lot in the zone.  But there were also a lot over the plate but below the zone.  A lot of pitchers that heavily feature a sinker do throw the pitch below the zone.  We saw this a couple days ago when Jeurys Familia chewed up Cubs hitters with sinkers low and inside.  All they had to do was lay off the pitches, but that's harder said than done.  If the sinker is effective it will look like a strike and then dive below the zone.  There's a reason our young hitters couldn't lay off that stuff.  Here's how Familia has used his sinker against right-handed hitters this year: 

 

That's not what Jake has done to be successful with his sinker, though.  Jake's at his best when he's throwing his sinker zone high.  He doesn't need to get it down below a hitter's hands, like Familia does, because it's so nasty that the hitter isn't going to do anything with it anyway.  The following are Jake's zone profiles with his sinker against left-handed hitters.  The first is from last year and the next is from this year. 

 

 

Last year's profile looks like what we saw in the strike zone plot of his no-hitter.  He liked working just off the outside of the zone.  This year it is going all over the place.  Next we'll look at his zone profile with the sinker to right-handed hitters.

 

 

Last year, he pounded the zone with it.  He liked to start it off the plate and then bring it back over to freeze guys, like in the gif from earlier.  But, really, he just challenged guys with it, too, knowing his stuff would win out.  This year, again, it's going all over the place.  But, most often, it is over the plate and below the zone, like we saw in last night's strike zone plot.  He's not able to throw it for strikes.  And not only that, but when he is below the zone, he's often well below the zone, as you can see on Fangraphs' 10X10 grid.

This problem only persists with his sinker, really.  He's using his slider in the same way this year as he was last year.  He throws it low and away to righties and low and in to lefties.  Same as before.  The same can be said about his curveball last year and this year.  He threw his four-seam fastball all over and around the zone last year, and he is doing the same this year.

The only difference is that he doesn't have command of his sinker this year.  And it's not that hitters have changed their approaches against him this year.  They just aren't getting fooled into swinging at pitches out of the zone, because the ones out of the zone don't look like strikes anymore.  Those pitches are either way off the zone, or they aren't high enough at any point to entice them.  Notice how much lower the average vertical pitch location has been with his sinker the last two months. 

 

He's also using sinker more and his slider less.  So he's relying more than ever on a pitch that he can't command. 

 

But, he's still got swing-and-miss stuff.  He's getting whiffs like usual.  He's also getting hitters to swing at his sinker roughly the same amount compared to last year, relative to their placement in the zone.   The following zone profiles are for hitters' swing rates against his sinker, with last year first and this year second.  First we have him against right-handed batters: 

 

 

  And then against left-handed batters: 

 

 

 

Hitters aren't really approaching the sinker any differently.  If he could hit his spot, they would be swinging just as often as before.  He can't put the sinker where he needs to put it, though.  The command isn't there.  There are a number of questions you might have:  Why...?  Why is this happening?  Is he injured?  Is it a mechanical issue?  Is it something that he can correct?  When will I get to see God-mode Arrieta again?

My answer to all of those questions:  I don't know.  Really, I don't have a clue.  Pitchers are weird.  This stuff happens.  I'm not the one to answer those questions.  Hopefully Jake and Chris Bosio can figure it out.  That's all we have... hope.  Obviously, it's not that easy to figure out.  If it were, Jake would have fixed it already.

There are a few things we can look at.  Several people have attempted to figure this out already.  Evan Altman at Cubs Insider noticed last month that Arrieta's vertical release point is higher than it was last year.  Brendan at Cubs Related delved further into this more recently.  He noted that Arrieta's release point started off higher this year, but that it is now back down where it was last year.  I would urge you to check out both of these articles, as they are both interesting and well-written.

Whenever something changes, the worry is that it might be due to injury.  There has been a lot of work done to see if we can predict pitching injuries.  I think Brendan's findings help dismiss the idea that Arrieta is injured.  The biggest harbingers of injury are a loss in velocity and inconsistencies in release point.  This is especially true in late-game situations.  If there is a loss of velocity or more variance in release points as a game goes along, it might be a sign that an injury is looming.  Brendan showed that Jake's in-game release point variance is normal.  We've also seen that his velocity is normal.  And, as Brendan states, pitchers have been known to change their release points for whatever reason.  He showed that Jon Lester's vertical release point is also higher this year.  And things are going fine there.

So if he's not injured, then what?  I don't know.  I would guess that it is something mechanical that needs fixed.  I don't think Jake forgot how to pitch.  Something is just awry.  Knowing Jake, he is going to work his ass off to fix whatever it is that ails him.  I think we have a really good pitching coach in Chris Bosio, too.  If Bosio and Arrieta were able to work together to fix Arrieta once, why not again?  They have some work in store.  Let's just hope they figure it out.

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