Arrieta’s Approach and Chicago’s Chances


For better or worse, Game 6 will go the way of Jake Arrieta (credit: Brian Cassella/Chicago Tribune)

– Bill Annechino

I have a friend who is a lifelong Cubs fan.  Before and during last night’s game 5, I told this friend that if the Cubs win, they are going to win the World Series.  At this point, the few people reading this column are probably asking themselves why I would think this, given that the Indians have had the Cubs’ number so far this series.  The answer to this question lies in the advantage I believe the Cubs will enjoy having Kyle Schwarber back in the lineup in the American League park as well as seeing Corey Kluber a third time in 9 days, but it starts with Game 6, and all eyes will be on Jake Arrieta, a pitcher who, since his arrival to the Cubs, has gone from a Quadruple-A type pitcher with the Orioles to a Cy Young winner.  The biggest part of his transformation has been, in my opinion, a sharp increase in the amount of ground balls that he is able to induce.  By looking at some of his pitching tendencies, I am going to outline a clear path for the Cubs to win Game 6 and induce the all-important Game 7. 

Please note that all stats in this article come from, unless otherwise mentioned. 

The biggest reason for the Arrieta transformation from Baltimore to Chicago was a change in pitch selection.  As an Oriole, Arrieta never threw his fastball less than 31.9% of the time, topping out at 43.7% in 2011.  In Chicago, Arrieta has thrown his fastball 21.5% of the time in 2014, 20.8% of the time this year and a mere 15.7% of the time in his Cy Young campaign from a season ago.  So, you’re probably wondering, what was he replacing the fastball with?  Well, in the last 2 years, he has shown an uptick in use of his sinker, but he had thrown a good amount of sinkers during his time with the Orioles.  What has changed in Chicago is that he is throwing his slider, and he’s throwing it a lot.  His first two years in Chicago, he threw his slider right around 30% of the time.  This year, he has thrown the slider a mere 18% of the time, which he has supplemented by going to his sinker 44% of the time.  Pitchers don’t just change their entire profile as a pitcher, especially after having the kind of success that Arrieta had with his wipeout slider.  If we dig deeper, there is another trend at play. 

Runs above average is a statistic that tells us, essentially, how effective a certain pitch was in terms of batters scoring runs against it.  It is not considered to be a predictive stat, but it can certainly be an explanatory one.  Note that the higher the positive value, the more effective a pitch was.  In 2014, Arrieta’s slider was worth 2.2 runs above average per 100 pitches (roughly the length of the average start).  In 2015, that number went all the way up to 2.4.  These numbers represent the highest value among all of his pitches.  Prior to his arrival in Chicago, the highest value he had ever posted with that pitch was a .46 back in 2011.  This year, however, the slider value has fallen all the way down to a 0.13.  This shows that the pitch that had been his best pitch had been relegated to effectively useless.  So, the big question is:  What changed? 

The easiest answer to this question is that hitters caught up to what Arrieta was doing and figured him out, so to speak.  In 2014 and 2015, about 26% of his strikeouts were coming via his slider, and only 5% of his walks.  In 2016, the strikeout number dropped to about 20%, and the walks rose to 11%.  In addition, the swing rate on the slider was 56.4% in 2014 and 58.7% in 2015, but fell to 51.9% this year.  In light of all this, Arrieta threw about 400 fewer sliders this year than he had in his Cy Young season in 2015.  Postseason baseball is a different animal, however, so I wanted to take a look at his pitch selection during these playoffs.  To do this, I headed over to

According to my research, Arrieta has thrown his slider more frequently in these playoffs than he did in his Cy Young season.  Arrieta is at his best when he is hammering batters with his power sinker, not getting them to swing and miss at his slider.  In 2015, he had a 17.18% whiff percentage on his slider, which is down to 13.9% in these playoffs.  When he was at his best, he had nearly an 11% ground ball rate on this same slider; in the 2016 playoffs, this number is down to 6.33%.  The data shows that batters are actually swinging at his slider more often in these playoffs than they did in 2015, though.  There’s a nearly identical ball rate between the two splits, but the strike rate decreased from almost 28% in 2015 to 24% in these playoffs.  In addition, there is a 4% increase in balls in play off the slider between 2015 and the 2016 playoffs.  We already talked about how the ground ball rate on the slider was a lot higher in 2015 than it has been in these playoffs, which means that guys were swinging over the top of the slider and hammering the ball into the ground for an easy out.  In fact, in 2015, Arrieta only had a 3.88% fly ball rate, a 0.94% pop-up rate, and a 0.28% home run rate.  In the 2016 playoffs, those numbers are up to an 8.86% fly ball rate, a 5.06% pop-up rate and a 1.27% home run rate.  At this point, I had a hunch about what was going on with Arrieta’s slider, but I wanted to take a look at one last piece of evidence before I made my final conclusion. 

I believe that the location of Arrieta’s slider has been elevated, which is the cause of many of his problems.  In his Cy Young season, batters hit .255 on sliders that they put in play, which is actually higher than the .222 they have hit this postseason.  In 2015, batters hit .186 against the slider, which is up to .200 in these playoffs.  That’s an increase, but a relatively small one and not one that I would consider to be especially significant.  However, I noticed a large statistical disparity in slugging percentage.  Isolated power (ISO) is a sabermetric stat that measures raw power by subtracting a hitter’s batting average from their slugging percentage to show how many extra bases a player averages per at bat.  In 2015, the ISO on Arrieta’s slider was a .084, which is tiny.  In these playoffs, that number has essentially doubled to a .160.  This means that hitters are roughly hitting the slider as much as in these playoffs as they were in Arrieta’s Cy Young season, when he was at his best.  However, the difference is that now when players hit the slider, they are elevating the ball and getting it into the outfield as opposed to driving it into the ground, which is the last result you want to see off of a pitcher’s breaking ball.  Now, let’s combine the statistical evidence we have with some of the anecdotal evidence available to give us a real picture of what is going on with Jake Arrieta. 

A pitcher’s mechanics are probably the most important part of their player profile, even more so than their pitch selection.  A guy can throw the nastiest slider in baseball, but if his mechanics are off, then his ability to consistently locate this pitch is not going to be there.  Arrieta is anecdotally said to have some unconventional mechanics, and if you watch him pitch, you know what I mean.  Far from the fluid mechanics of noted control pitchers like Mariano Rivera or Greg Maddox (fluid, easily repeatable), Arrieta employs a herky-jerky motion where the ball explodes out of his hand.  On one hand, it makes it harder for a batter to track the ball, but it also makes it difficult for the pitcher to consistently put the ball in the same spot.  Many observers have noticed that Arrieta has struggled with control issues this season, and the sudden issue with what was his best pitch seems to be the result of these mechanical issues.  Normally, this is the kind of thing that an elite player can correct over an offseason, under the tutelage of a pitching coach.  Jake Arrieta is pitching the 6th game of the World Series on Tuesday night, so he doesn’t really have that luxury.  However, I think there is a clear blueprint to him pitching his team to a win. 


(credit: Anthony Souffle/TNS)

Remember at the beginning of this column, I led by saying that I believe the Cubs will win Game 6 and ultimately go on to take the Series in 7?  Well, despite everything negative I have said about Jake Arrieta in this column, I still think this is going to happen, and here’s why:  He still has his devastating sinker, and it’s as good as it has ever been.  In his Cy Young season, hitters batted .198 against the sinker, with an ISO of .079.  In the 2016 playoffs, that batting average is down to .156, and the ISO is at a microscopic .063.  You may remember that Arrieta was dominating in Game 2, flirting with a no-hitter for much of his start, so let’s look at what happened in that game. 

More than half of the pitches Arrieta threw in Game 2 were sinkers.  The Indians whiffed on 10% of the sinkers he threw, and hit almost half of them foul.  In total, only 4 sinkers were put in play, 1 of which dropped for a hit.  The slider, on the other hand, was not as sharp.  Of the 21 sliders Arrieta threw, more than a third (8) of them were put in play.  Only 1 dropped for a hit, but those numbers point to a pitcher who got lucky:  the league average for batting average on balls in play is right around .300, with anything higher or lower suggesting luck and a regression coming.  Arrieta was playing with fire, letting 8 of his sliders be put into play; the fact that only one ended up being a hit does not mean that this is sustainable.  It is also notable that these 8 balls in play came on 12 swings, which means that there was only one whiff on this breaking pitch and suggests that the slider was not fooling anyone.  Luckily for Arrieta and the Cubs, Indians hitters were swinging at almost a third of the sinkers he threw (29.4%), and were not able to do much damage.  I think that this data shows a pretty clear game plan for Arrieta in Game 6:  lean on the sinker. 

If Arrieta can get away from throwing his slider and feed the Indians a steady diet of sinkers, as he did in Game 2, the Cubs should win this game, especially with Kyle Schwarber in the lineup as a DH.  In Game 1, with Schwarber hitting .333 behind him, Ben Zobrist hit .750.  This continued into Game 2, with both hitters going 2 of 4, and combining for 3 RBIs.  In Games 3 through 6, without Schwarber’s protection, Zobrist went 2 of 11.  Lineup protection is a major factor in baseball, and the impact that Schwarber’s bat has on not only his statistics, but the statistics of the dangerous hitter in front of him show that his presence is crucial for the Cubs. 

The gameplan for a Cubs victory looks like this:  Jake Arrieta leans heavily on his sinker and Kyle Schwarber protects Ben Zobrist.  Schwarber has proven himself to be a reliable postseason hitter, and Zobrist has been dominant with Schwarber behind him.  We all know what Kris Bryant is, as he has continued his likely-MVP caliber hitting into the postseason.  Anthony Rizzo’s bat has also come alive this World Series.  As long as the all-important Dexter Fowler can get on base ahead of the Cubs’ big bats, the offense should be primed to take advantage of a strong matchup against Josh Tomlin.  When the situation is a win-or-go-home World Series game, with the reigning Cy Young winner going to the mound, you have to like your chances, and if Arrieta feeds the Indians a steady diet of sinkers, I believe the Cubs will force a Game 7, in which I have confidence that the combination of Kyle Hendricks’ strong pitching and familiarity with Corey Kluber will lead to the Cubs’ first World Series title in 108 years.

Bill Annechino

– Bill Annechino (@BillAnnechino)


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