Jake Arrieta’s Struggles are Really Interesting

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It isn’t really breaking news that Jake Arrieta hasn’t been the same pitcher we’ve seen over the last few years to this point in 2017.  Even when he struggled with command in the second half last season, the results weren’t so strikingly awful. As we sit here today, through 8 starts, Jake Arrieta has a 5.44 ERA and 4.15 FIP.  It isn’t all bad, though.  The 9.87 K/9 would be a career best and the 2.62 BB/9 would be back in line with when Jake was pitching as a bona fide ace.  The difference is he’s getting hit more.  A lot more.

Before going into depth, the timing of this piece has been preceded by some other fantastic insights.  Jeff Sullivan over at Fangraphs wrote a very strong piece on this subject.  In the interest of disclosure, we cover some of the same types of ground.  And I wanted to ensure I give him his due…because his piece, linked here...is outstanding.  Now, onto my discussion…

Whenever a pitcher goes through a remarkable downturn, as Jake Arrieta so obviously has, the first thing that typically gets asked is, “How’s his velocity?”  This isn’t really specific to Arrieta this season, as the entire rotation has seen a dip, but Jake’s is obvious and it’s stayed down.  Last season, Arrieta’s four seam fastball and sinker were in the 95 mph range for much of the season, although they took slight drops in August and September.  A simple explanation for that would be that the Cubs were up a bunch and he took his foot off the gas.  And he cranked it back up in the World Series.  Emptied the tank, if you will.  2017 has seen him live in the 92-93 area.  The decline isn’t exclusive to his fastball and sinker, either.  Jake’s declined across the board.  And while that’s somewhat concerning, it’s difficult to pin everything that has gone wrong for him on a couple of ticks off the radar gun.

Looking at Jake’s release point may contain some of the answer.  Since arriving in Chicago and pitching with the Cubs, Jake’s vertical release point has been fairly consistent.  He has lived in the same basic regions in all but one season…2016.  In 2016, his release trended up a couple of inches, nearly across the board.  This was more remarkably seen in the later portion of the season, when Jake struggled more with commanding his pitches.  This season, his vertical release point seems be be back down to where it was when Jake was the ace of the staff.  One notable exception is his curveball, which he is releasing lower than he has previously as a Cub.

Jake Arrieta Vertical Release Point via Brooks Baseball
Jake Arrieta Horizontal Release Point Via Brooks Baseball

Looking at the bottom chart, we can also see what Jeff Sullivan pointed out…Jake’s horizontal release point has ventured out toward third base more this season than it has ever before.  Seeing that his release point has essentially moved back down and to the third base side makes his vertical movement numbers interesting.  Across the board, the vertical numbers have come down.  And with his pitches living in the strike zone more, it isn’t a big surprise that what appears to be flatter pitches getting hit in the air more.  His downward movement used to generate a ton of ground balls. At current, he’s being hit in the air a lot more, and he’s being hit harder (although, not hard.  More in a moment)…which is why he’s allowed 8 HRs in 8 starts, a 1.61 HR/9…which would be a career worst for Arrieta.

One interesting note, however, is Jake’s average exit velocity.  Among pitchers with 130 or more batted ball events, Arrieta has the 4th lowest  average exit velocity.  And the 2nd lowest average fly ball exit velocity.  And has been hit at 95+ mph only 36 times, also second fewest among pitchers with 130+ batted ball events.  These numbers are what make it complicated for Arrieta right now..  He’s getting hit hard more frequently (although not alarmingly frequently), and when he does bad things almost always happen. His average exit velocity is about 85, which is actually down from his 86 mph average last season.  And is in some line with the 84 he posted for the 2015 season.  In short, his overall numbers are pretty close to the Jake Arrieta we know to dominate baseball games, but when it does get squared up, it ends badly.  And that’s been happening more often this season.

There are some speculative reasons for why Jake Arrieta continues to struggle after about a quarter of his 2017 starts.  The first is that he hasn’t cranked it all the way up yet…a “saving gas for a postseason run” theory.  That’s all well and good.  It’s hard to envision that being true in a contract year.  Baseball teams are going to look hard at what is going on here and what happened last season toward the end of the year when weighing whether he’s worth a 9 figure contract.

Based on his ball in play numbers, part of the reason his numbers look so bad is bad luck.  And he has pitched in some larger parks.  Coors Field and Fenway have accounted for 10 of the 27 earned runs he’s allowed to this point.  And he’s faced some teams at inopportune times, coming into match-ups against teams who are locked in and hitting the ball well, which makes his need to be more precise greater.  It certainly isn’t all bad luck, but he hasn’t exactly gotten the benefit of being able to make a mistake yet this season.  Even the best pitchers need some luck now and then.

The last thing could be injury.  The way he’s releasing the ball could point to something physical.  It’s irresponsible to speculate that could be the case, and that’s not the point of its addition to this post.  The point is that it’s not wise to rule it out.  If Jake is injured in some real way, it could explain the alteration in mechanics and dip in velocity.  It may also explain why he’s so much better as the game wears on.  His numbers the first and second time through the order are not good.  7.16 ERA the first time through.  5.87 the second.  A Jake Arrieta like 2.77 the third time through.  And the slash lines go in similar order.  He gets much better later in his starts, with the exception of his walk rate.  That isn’t a surprise, though, as command usually suffers first when a pitcher begins to tire.  If he has an injury issue that gets better as he progresses through a start (“tightness” that players leave with regularly), it could be causing some of his slow starts.  It could also be, just as easily, that Jake Arrieta has funky mechanics and they’re easy to get out of whack…and when he finds them and has them consistently, he’s as good as there is in MLB.

After looking into the numbers, it’s fair to say I’m more confused about Jake Arrieta than I was before I started.  The overall numbers look and are bad.  Some of the deeper stuff looks like the Arrieta of the last few years.  As the season wears on, it’ll be interesting to see if the overall numbers start to regress (which I am now convinced they should), if his velocity recovers, and if some of the lost movement comes back.  The only fair assertion to make at this point is that the results need to start turning around.  And there is some strong reason to believe that they will.



Feature Image from Matthew Stockman/Getty Images via ESPNChicago
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About Andy

Sometimes I write stuff about the Cubs. Sometimes it's even good. But don't get your hopes up. Basically, my writing is like the pre-2016 Chicago Cubs.

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