Mike Napoli is Being Shafted by the New Strike Zone


Scoring has been down across Major League Baseball for a few years now. The main culprit is the expanded strike zone, which has led to more strikeouts. Ian York takes a look to see if Mike Napoli is being shafted more than the rest of the league.

The strike zone has been expanding from year to year since 2010. The zone in 2015 is larger than it was in 2014, just as the 2014 zone was larger than the 2013 zone. This means that more strikes are being called on pitches that the prior year would have been called balls. 

This must be frustrating to batters (just as it must be a delightful surprise to pitchers and catchers), and a particular type of batter is most likely to find this a difficult change. Right-handed batters will be disproportionately victimized, since the right-handed batter’s strike zone has expanded more than the lefties’ zone. Batters who pride themselves on their ability to recognize the strike zone, and to take the pitches that are outside it, will find themselves taking called strikes that, according to their experience, should have been called balls.

Which brings us to Mike Napoli, a right-handed batter who prides himself on his knowledge of the strike zone, and who, as reported by Alex Speier at the Boston Globe, has complained recently about the expanding strike zone:

Napoli said, “I think the strike zone is bigger and pitching is better. That’s a double whammy right there … I have a good feel for the strike zone and where it’s at. I think that’s where my frustration comes.”

Is Napoli right? Is he disproportionately impacted by the newly-expanded strike zone?

By looking at Napoli’s called strikes in each year, and asking which of those would not have been called strikes the previous year, we can see how much the changing strike zone affects his called strikes. For this, I will use the zone margins that I have previously defined. These are the regions where a pitch has a 50/50 chance of being called a strike. Here is what those zones look like, as they have changed over the course of each season from 2008 through 2014:

In these charts, which are from the umpire’s viewpoint, pitches in the blue areas have almost no chance of being called a strike, those in the green areas are almost certain to be called strikes, and those in the red areas are intermediate; the white polygons overlaid on each represent the path of the 50% probability for the overall year, with a little bit of smoothing.

Baseball-wide, here are the percentage of called strikes that would not have been inside that 50% strike path the previous year:

Year Left-handed batters Right-handed batters
2011 1.5% 2.8%
2012 0.6% 0.3%
2013 0.8% 0.1%
2014 0.5% 2.0%

Note the relatively large effects in 2011 and 2014; these were years in which the zone abruptly expanded relative to the previous year. And note also that in both those years, right-handed batters were much more affected than lefties; the zone to right-handed batters has been made disproportionately larger.

Here are the data for Mike Napoli:

Year Newly-called strikes
2011 4.8%
2012 1.5%
2013 0.9%
2014 3.5%

Year after year, Napoli has indeed had a significantly higher percentage of strike calls that he could legitimately consider unfair, in that they would have been balls in the previous year:

Since there are not yet enough data to confidently define a strike zone for 2015, it is too early to try to put a concrete number on how many of Napoli’s called strikes this year would have been out of the zone last year. However, we can look at where these pitches fall, and compare to the areas that seem to be expanding this year compared to 2014. I will overlay called strikes to Napoli in 2015 that are outside the 2014 strike zone, on a chart showing the difference in strike probability for 2015 vs 2014. Pitches in regions that are red in this chart are more likely to be called strikes than they were in 2014. The 2014 strike zone is the grey polygon here:

Some of these called strikes are simply bad calls, but most of them are in a very specific place, just outside the outer edge of the 2014 strike zone. This is one of the regions that has the most red; that is, it seems to be expanding in 2015. 

John Farrell has specifically called out a widening strike zone this year, as Michael Silverman reports: “There’s been a lot of pushback at field level, because the strike zone is clearly wider.” Even though the difference across all of baseball may not be large, Mike Napoli, in particular, has clearly received enough called strikes on pitches that are outside last year’s strike zone – 10 of the 162 called strikes he has seen this year; 6.2% – that he does have real cause to complain.

That said, five or six percent is not large. The vast majority of the strikes that are called on Napoli are correctly called in the context of last year’s strike zone. Certainly over a full season, ten or twenty extra called strikes in themselves are not enough to lead to Napoli’s so-far disappointing season. However, the impact of these called strikes may well be disproportionate to their number, forcing Napoli to doubt his own strike zone judgement and perhaps swing at pitches he would normally and correctly take. As Alex Speier reported Napoli acknowledges both of these points:

“People might say, ‘It’s one pitch,’ but that’s one pitch where he has to think about throwing me a heater rather than trying to screw around and make me chase something. He has a pitch to mess around on when he’s 0-1 or I’m 0-2 instead of 2-0 or 1-1. It’s tough. (But) it’s not an excuse.”

Napoli is right on both accounts. On the one hand, he is getting exceptionally hurt by the changing strike zone and has been for the past couple of years, and it is probably one of the things affecting his batting. On the other hand, while he is unusual, he is not alone; other players are also hurt by the changing strike zone, and not all those players have seen their numbers drop to the same extent as Napoli. Most importantly, the zone is probably never going back. The strike zone is what it is, no matter how unfair it may be to particular players, and their only choice is either to evolve or to perish.

Ian York looked at Eduardo Rodriguez’s first start and David Ortiz’s struggles with fastballs from left-handers.

Follow Ian on Twitter @iayork.

Check out Sean O’Neill’s article about Todd Frazier’s post-breakout breakout.