Prince’s Improved Approach at the Plate

A premier name in an uninspiring free agent class, Prince Fielder will make his money through his powerful bat. But matching his ability at the plate is his tremendous rotundity. This is a legitimate concern, as based on the careers of similarly bodied players Fielder does not project to age well.

While teams would be correct to worry about his weight, they would be downright foolish to doubt his bat. Already elite at the plate, Fielder is fresh off his best offensive season, as measured by wRC+. Key to his success this past season was his improved plate discipline. While already talented in his plate approach, Fielder took last year to another level. As Dave Cameron observed earlier in the year, Fielder dramatically reduced his strikeout rate.

But before we look at what Fielder is or isn’t doing differently, we need to recognize that there are two parts to the batter-pitcher match up. Perhaps obvious, but sometimes we credit all changes in walk and strikeout rates to the batter, without considering pitchers’ approaches.

Did pitchers approach Fielder differently in 2011?

This graph shows the density of pitch locations thrown to Fielder in two time ranges, 2011 and 2008-2010. I did not include PITCHf/x data from 2007 because the data quality when the system was first being set up was a little suspect. The color in the graphs indicates the frequency of a pitch, where black indicates a high frequency of pitches and white indicates no pitches. The dotted box represents the strikezone, and the graph is from the catcher’s perspective. This means that the right side of the graphs are closer to the inside of the plate for Fielder, and that the left side is closer to the outside part of the plate to Fielder.

Pitchers mainly locate low-and-away to Fielder — no surprise given his prodigious power. According to these graphs, his pitch locations were pretty similar in both years. Of course this analysis is not very rigorous. As a quick sanity check, if we look at his in zone rates — the percentage of pitches thrown within the called strikezone — we find that he was thrown 43.4% of pitches in the zone in 2008-2010 and 42.4% in 2011. This difference is pretty negligible, and is not statistically significant.

It’s also possible that pitch selection to Fielder has changed. To test this, I looked at all of his pitches and grouped the Gameday classifications into three categories: fastballs, breaking balls, and off-speed pitches. Fastballs include four-seams, two-seams, and cutters. Off-speed includes changeups and splitters. Breaking balls include sliders and curves. I created these large groups to deal with Gameday classification issues.

years 	  pitch type  	proportion
2008-2010 Breaking ball 0.252
2008-2010     Fastballs 0.574
2008-2010     Off-speed 0.174
     2011 Breaking ball 0.274
     2011     Fastballs 0.550
     2011     Off-speed 0.175

As you can see, the two sets of pitch selection are very similar. It seems then that we can conclude that pitchers’ approaches to Fielder were pretty much the same in 2011 as in 2008-2010.

Fielder’s Changes

The Brewer’s first baseman greatly improved his contact rate in 2011, raising his contact rate from 76% in 2008-2010 to 80% in 2011, a difference that is statistically significant. Where in the zone did his contact rate improve?

The graph shows his whiff rate (whiffs/pitches) by horizontal pitch location, with gray bands indicating confidence. The dotted lines indicate the horizontal borders of the strikezone. It seems that his contact improvements came on pitches down the middle, although the difference in whiff rates is still pretty small.

This graph displays the areas in which he made at least 90 percent contact (1 – whiff/swing). As you can see, he expanded his 90% contact contour in 2011 to span more of the strikezone.

I don’t know what mechanical adjustment Fielder made  — if any adjustment — to improve his strikeout rate. But whatever he did, he helped to round out an offensive skill set that was already excellent. Driven by a higher contact rate, a large amount of regression to his 2008-2011 strikeout rate does not seem likely. Contact rate stabilizes very quickly, and correlates very well in consecutive years. Incredibly, Prince Fielder became harder for pitchers to deal with in 2011 — and probably the future as well.

References and Resources

• PITCHf/x data from MLBAM via Darrel Zimmerman’s pbp2 database and scripts by Joseph Adler/Mike Fast/Darrel Zimmerman
• Strikezone definitions from Mike Fast’s research
• Plate discipline statistics calculated by author with PITCHf/x data