Do Pitchers Induce More Ground Balls in Double Play Situations?

Earlier this week I was gallivanting around Fangraphs' criminally underused Q&A section when a user caught my eye with this question for the saber world: "Does a batter's GB% raise, drop or remain even with a runner at first?"

Seems like a reasonable assumption, right? In bases-empty situations, a pitcher may not concern himself so much with inducing a ground ball as opposed to simply just working an out by any means necessary. But, with a runner on first, of course, a ground ball out becomes especially attractive as it creates the opportunity for the ever-valuable double play.

I ran the data and found that since 2002, GB% (as in GB/batted balls) with Bases Empty was 44.9% across the league. With a runner on first and the double play now a possibility, that number actually drops to 43.7%. Now, I'm going to ignore the drop and assume its just noise, but I will admit to being mildly amused by this. (This is using retrosheet's definitions of batted ball types, keep in mind, and BIS data may differ.)

Curious, I then ran the data again and included only situations with less than 2 outs, when the double play would be beneficial. But even then there was no change:

BATTED BALL BY BASE-STATE

BASE STATE	GB%	FB%	LD%	PU%*
Bases Empty	44.7	37.1	18.2	7.9
"1--"	43.7	37.3	19	7.6
"-2-"	46.8	35.2	18	7.5
"12-"	44.3	37.4	18.3	7.5
"--3"	44.7	37.5	17.7	7.6
"1-3"	44.9	37.7	17.4	7.5
"-23"	46.1	36.4	17.4	7.4
"123"	44.2	38.4	17.4	8.2

*FB% includes "pop-ups"

And then I ran the data once more using Plate Appearances as the denominator, just to make sure some non-batted ball events weren't interfering with the results, but still nothing:

BASE_STATE	GB%	FB%	LD%	PU%
Bases Empty	31.8	26.4	12.9	5.6
"1--"	30.3	25.9	13.2	5.3
"-2-"	30.3	22.8	11.7	4.9
"12-"	29.7	25	12.2	5
"--3"	30.2	25.3	12	5.1
"1-3"	32.4	27.3	12.5	5.4
"-23"	28.3	22.4	10.7	4.6
"123"	32.7	28.4	12.8	6.1

Of course, inducing ground balls isn't every pitcher's forte. So I kept that same time frame, 2002-2011, and restricted the search to only those pitchers who posted a ground ball rate of at least 50% over at least 500 innings. I queried their GB% with both bases empty and in "double play situations", which I defined as base-states 1--, 12-, 1-3, and 123, with fewer than 2 outs.

On average that group posted a GB-rate of 54.4% with the bases empty, and in double play situations 54.04%. So no change there either, but that may not be saying much-- if your best weapon is a sinker or 2-seamer that induces a high rate of grounders, why limit it to just Double Play Situations?

So by this point, you're probably thinking the same thing I was thinking: enough of this nonsense, just show me which pitchers actually do induce more grounders in double play situations. Can do:

#	First	Last	IP	GB%	GB% BE	GB% DPS	Diff
1	Billy	Wagner	566.7	43.9	40.8	49.3	8.5
2	Scott	Linebrink	637.7	37.8	36.1	43.4	7.3
3	Brad	Lidge	639.3	41.7	39.1	45	5.9
4	Mariano	Rivera	740.3	54.7	53	58.2	5.2
5	Adam	Eaton	927	40.3	38.3	43.3	5
6	Carlos	Silva	1246.7	48.9	47.5	51.9	4.4
7	Jason	Jennings	1089	46.6	46.2	50.6	4.4
8	Kirk	Saarloos	509	56.7	55.1	59.4	4.3
9	Jason	Johnson	872	51	49.5	53.6	4.1
10	Chris	Young	782.3	28.2	27.4	31.4	4

Now, I've run some pretty bizarre queries in my time. I'm not kidding you-- I've sifted out things as ridiculous as night-game wOBA with RISP and 2-outs on get-away days in September for the Montreal Expos. Believe me, there is an unending universe of small samples that lie deep, deep within the retrosheet files.

But never in my life have I run a top ten list that returns the one-and-only Mariano Rivera next to a one Adam Eaton. I mean, he doesn't even deserve a hyperlink!

So, we are likely seeing quite a bit of noise here. But, if I was to be convinced that anyone had the capacity to induce ground balls on demand in situations where the batter was positively trying to avoid such an outcome, I would put my money on The Sandman. Not to take anything away from Billy Wagner, whose 8.5% difference makes an interesting case as well. Considering that the 10th greatest surge in GB-rate during DPS was only 4%, Wagner's 8.5% is certainly compelling.

Both Brad Lidge and Scott Linebrink had brief (ok, very brief) stretches where they seemed to have performed close to the Wagner/Rivera level, but I'm nowhere near sold on that. Carlos Silva frequently posted ERA's lower than his FIP during his time with Minnesota, and inducing an inordinate amount of double plays could have been a contributor to that in theory. And it's conceivable Chris Young, an extreme fly ball pitcher, could have altered his pitch selection slightly in double-play situations, becoming a not-so-extreme fly ball pitcher in those conditions. But that's a long walk.

I have little doubt there is a deliberate effort on the pitchers part to induce grounders when they can benefit them the most. But what we may be witnessing in these tables is the opposing efforts of the hitter responding to the situation as well, counteracting and neutralizing that deliberate effort.

In extreme cases, the elite pitcher may win out. In other cases, a dude might just be getting lucky.

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