Time To Worry About Mo?

Is his location to lefties different?

This graph shows Mariano’s pitch location to left handed batters in 2010 and 2011, where red is 2011 and blue is 2010. Each contour represents the same proportion of Mariano’s total number of pitches to lefties. The graph is from the catcher’s perspective, and the dotted box indicates the left-handed batter’s strikezone.

According to this graph, his location was pretty similar in both years. Much like the visualization presented in Simon’s article, it seems that his cutters in 2011 are leaking a little more over the middle of the plate. But how much of this is an artifact of the plotting system? Consider the graph below, which uses the same exact data as the graph above, in addition to the same kernel density smoothing method.

Pitch location now looks identical! What’s different? I reduced the number of bins by a factor of 10.  Am I implying that the graphs in the article were made incorrectly? No. The point of me showing these two graphs is that you can often reach a different conclusion with one small, arbitrary tweak in your plotting method if the differences are small to begin with.

We must also consider the role of PITCHf/x calibration error. PITCHf/x works by using three cameras that take a series of images of the pitched baseball while in flight. Nine parameters are recorded: position, velocity, and acceleration in each of the three dimensions. From these parameters we can then extrapolate location, movement, and break. However, these cameras are not always completely accurate. Consider the work of Max Marchi and Mike Fast, who both show that the cameras often incorrectly estimate pitch location by small, but significant amounts. Given the pervasiveness of these small errors it’s hard to confidently say that Mo’s pitch location in 2011 is significantly different from 2010. We should also consider that I have not accounted for differences in the context of these pitches. By this I mean that Mo throws to different locations in different counts (0-0 vs. 0-2), so if Mo has had a different distribution of counts this year then he could have a different pitch location graph while still throwing to the same locations in each count! This is similar to Simpsons’ paradox.

For the above reasons it’s pretty hard to say that there is a notable difference in his pitch location to lefties. However, lets assume that his location is actually different in a significant manner, for the purposes of this post.

Is his new location better or worse?

To evaluate this, I created a model that predicts the quality of Mo’s pitches based on location, using all of his pitches to lefties from 2008-2011. This is 1880 pitches, which is unfortunately kind of small for this kind of analysis (full seasons for starting pitchers are usually over 3000 pitches).

Red indicates locations where Mo performs best, blue indicates locations where he performs the worst. Like the other graphs, it is from the catcher’s perspective. The dotted black box indicates the strikezone for the average left-handed batter. The most blue areas are very far away from the strikezone, because in these areas pitches are always called balls.

As you can see, he is effective pretty much every where in the zone. Does this mean that he should forget about location and just throw it down the middle? No (this is kind of a game theory thing), but he can certainly miss his spot without getting hurt. We can use this model to look at the quality of his pitch location in 2010 and 2011. After normalizing my run values for differing run environments (linear weights made from a few years ago average in the negatives for 2010 and 2011), the model predicts that his pitch locations in 2010 should result in -2 run per every 100 pitches. This is an excellent value, as negative values are very good for pitchers (opposite of Fangraphs). When we use the 2011 data, the model predicts -2.2 runs per every 100 pitches – even better!

However, some caution is needed given the small sample used to create the model. The best conclusion that we can arrive at is that there is no reason to believe that his pitch locations in 2011 are worse than in 2010.

Finishing Thoughts

It’s hard to say that his pitch location to lefties is any different in 2011 than 2010. This is reflected in both visualizations of his pitch locations and a regression model used to predict run value. According to the PITCHf/x data, there really isn’t anything worrisome at all. In terms of velocity and movement, the pitch is identical to 2010. In a near perfect career, Mo has had a few blips every once in a while, and this is just another one of those blips. It’s not like he just rolled out of bed a few days ago without the cutter working after it being effective the entire season.

References and Resources

*PITCHf/x data from MLBAM via Darrel Zimmerman’s pbp2 database and scripts by Joseph Adler/Mike Fast/Darrel Zimmerman
*Mo’s player page on Fangraphs
You can follow Josh on twitter @J__Stock.

13 thoughts on “Time To Worry About Mo?

  1. Anecdotally I always remember Mo as having 2 "slumps" a year, one early, usually somewhere in April to early May, and one in the first few weeks of August. In these slumps, which last for a few games, he blows saves, gives up home runs and generally looks human. Then the storm passes and he becomes unhittable once again. This is just his August slump. I hope.

  2. Is he as dominant as he used to be? No. Is he still better than everybody else? Yes. Give me Mo over any other closer any day.

  3. As you've shown with the graphs, stats and numbers can prove whatever you want them to prove. I was forced to hit Fangraphs yesterday, to back my assertions that Mo was getting most of his "good" numbers in low leverage situations. Since that was my goal, I WAS able to prove that – he has allowed more runs and hits in fewer innings, comparing "high leverage" to "medium and low leverage" situations, combined. His road/home splits also show a marked drop-off in performance when he is away from home.

    What I couldn't find was how he did against good vs. bad teams. From what I've seen this year, most of his "clean" innings – the ones that pad his good numbers – have been against lesser teams, and even against the lower part of the order of lesser teams. That is the number I'd really like to see – because just as the teams scoring 17 runs against the White Sox or Mariners isn't really relevant when facing the BoSox, Mo's ability to dominate the bottom of the Mets order likewise isn't going to translate that well in the playoffs.

  4. Did anyone see those ridiculous david schoenfield twitter postings about how the yankee dynasty didn't need rivera because the world series were mostly 4 or 5 game affairs? Sure, there series weren't close, but nearly all the games were in every postseason series. Mariano Rivera is what let the yankees win all those world series in the 90s while the braves won one.

  5. This is baseball analysis by accountants. What's relevant about Rivera is the number of swings-and-misses and the break on the cutter. Are hitters swinging and missing as in past? Are hitters able to square-up his cutter?
    In the past, he broke more bats then pitches that hitters were able to square up. He struck out many more hitters then IP. In addition, watch the hitters' reaction to his pitches…many more aggressive swings.

  6. Even if he blows up a couple more times this season, 2011 is still as good, if not better, than a few of his earlier seasons.

    Also, is there stats for when Cervelli catches him and when Martin catches him? I know that I'm being a bit crazy here but the results could be interesting (or uninteresting, because I don't know the results) .

  7. If the Yankees do not make it out of the first round of the playoffs (or, gasp, do not make the playoffs) it will NOT be because of Mariano Rivera. I don't have any numbers or graphs to support this. It's just something I've picked up by watching a few baseball games in my lifetime.