21 May 2013

Wei-Yin Chen: Double Play Machine

by Nate Delong 
Delong writes about the Orioles over at Orioles Proving Ground. He is part of 2013's Expanded Roster, a feature where we provide local writers opportunities to expand their reach. Click here to find all of Camden Depot's Expanded Roster entries for 2012. 2011 Expanded Roster items can be found here. As always, feel free to provide the Depot with suggestions for posts or with your own interest in writing an items or several to be posted here.

Wei-Yin Chen recently went on the 15-day disabled list with a right oblique strain. As Matt Kremnitzer pointed out last week, Chen’s injury could cause some problems for an Orioles rotation that already ranks towards the bottom of the league in both ERA (23rd) and FIP (27th). Chen has easily been the most valuable member of the rotation this year, already accumulating 1.2 WAR in the first quarter of the season according to Fangraphs (2.2 WAR in all of 2012). His success this year comes mainly from his ability to keep the ball in the park, strand baserunners, and induce the double play.

Let’s focus on the final reason for his success. Wei-Yin Chen is not a ground ball pitcher. The league average GB% is usually around 44% (45.1% in 2012 and 44.6% in 2013). One look at the table below, and we see that Chen has been well below that in both 2012 and 2013.

Last year, Chen induced a total of 10 double plays. At the time he went on the disabled list this week, he had already matched last season’s total, despite getting opposing hitters to hit far less ground balls compared to last year. He is currently tied for second most double plays induced, behind Lucas Harrell (with 12), whose career GB% is just under 56%.

Let’s take a closer look at his double plays from 2013. Below is a table showing a couple of details for each of his double plays this year, followed by a corresponding figure that displays the pitch location of the double play (from the catcher’s prospective).*

*Pitch type and pitch location figures are courtesy of Brooks Baseball.

The first thing that pops out is the fact that Chen got away with a few pitches that could have been absolutely crushed, with half of them located over the plate, waist level or higher. Next, out of the players that hit double plays, at least half of them were hit by batters who are legitimately fast, indicating the balls were likely hit hard, right at the defender. Interestingly enough, only one of the groundballs was classified as weak (according to Baseball-Reference).

You’re probably thinking that Chen’s double plays in 2013 are just extreme good luck in a small sample, but just for fun, let’s take a look at the double plays from last year. The following table and figure show the same information as above, but for 2012.

All but 2 of the double play groundballs from 2012 were considered weak (I’m including the bunt as a weak groundball, as it’s probably safe to assume it wasn’t a scorcher), and it seems to make more sense, as Chen got more of these double plays from batters making contact on pitches located on the edge (or even out) of the strikezone.

Compared to last year, Chen’s double plays in 2013 certainly look like a function of good luck, especially considering the pitch locations. However, as a friend and I were discussing, the vastly improved infield defense could play a part in this increase as well. Beware of the very small sample in UZR/150 in the table below (UZR tends to stabilize after 3 years of fielding data), but it’s clear to see from both advanced and standard statistics (or with your own eyes while watching games) that this year’s infield defense is far superior to last year’s.

In fact, the entire Orioles pitching staff is on pace this year to shatter the number of double plays recorded in 2012. Through 40 games, the Orioles have turned 38 double plays, and if they maintain that pace, they’ll reach 154 by the end of the season, compared to 131 in 2012. Chen may have lady luck to thank for his increase in double plays this year, but it’s important to remember that he may have his improved infield defense to thank as well.

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