Where have the double-plays gone?

by Jim McLennan on May 19, 2008 10:49 PM EDT

The years 2005-2007 were something of a golden era for the twin killing in Arizona. Over the first seven seasons, the team averaged 109 double-plays per year, with a high of 120. However, likely triggered by the blossoming of Brandon Webb as a ground-ball pitcher, there has been an explosion over recent seasons. We surged to a record 141 in 2005, and have come close to matching that figure in both seasons since, notching 139 in 2006 and 138 last year.

The trend has come to an abrupt halt of late. So far in this season, through the first 44 games we have only 25, which would be on pace for just 92. This would be easily a franchise record low, beneath the previous worst of 97, set in 2002. And yet, as shoewizard recently pointed out, our defensive efficiency [the percentage of balls in play converted to outs] is excellent. Let's take a closer look, and see if we can find out what has happened to cause such a sharp reduction.

Stepping back to last year, we had 138 DP's in a total of 5,513 at-bats: one every forty, more or less. Perhaps surprisingly, Webb was below average, getting a double-play ever 44.2 at-bats; Doug Davis was the most impressive among the starters, with 23 in 750 at-bats, a rate of 32.6 . Here are the rates for the other pitchers who had 200 at-bats or more last season, and 60 or more this season.

Name	2007	2008
Webb	44.2	33.1
Hernandez	36.5	N/A
Davis	32.6	N/A
Owings	44.4	Inf.
Gonzalez	33.2	30.8
Pena	27.6	79.0
Lyon	39.9	Inf.
Valverde	47.0	N/A
Cruz	110.0	60.0
Petit	55.9	N/A
Johnson	70.7	152.0
Haren	N/A	105.0
Qualls	N/A	20.0
Medders	N/A	72.0
Scherzer	N/A	70.0

A couple of numbers stand out there. Replacing Hernandez 2.0 with Dan Haren has resulted in a significant hit to the double-play rate. On the at-bats for Haren so far, Livan 2007 would have been expected to roll up six double-plays; Haren has only two. This is somewhat surprising, as I'd have thought his splitter was a great pitch to induce ground-balls - his career rate is 48.3, so based on that, we should expect some more from him going forward.

There are also a few "Inf", which means the pitchers concerned have yet to record a double-play this season. Micah Owings is the leader there, 187 at-bats this year, and 47 of those came with a man on first, but no double-plays have resulted. That's somewhat remarkable, given his hit trajectory shows 36% of plate-appearances result in a ground-ball. Between, Owings, Lyon and Johnson, there have been 416 at-bats, and the first ground-ball double-play for any of them only took place yesterday, when Johnson got one on the opening inning. While the Big Unit has never been reliant on such things [his career rate is over 60], Owings and Lyon had perfectly respectable GIDP rates last season, so their sudden phobia of them is surprising.

Let's also look at where those double-plays were hit, and compare the figures to last year, to see if there has been any change in the distribution. To do this, I looked at the distribution from 2007 - the positions listed below are the ones which started the groundball double-plays [I'm excluding line-drive or fly-ball double plays, but including bunt attempts]:

Pos	DP %
2B	35%
SS	30%
3B	23%
P	7%
1B	4%
C	1%

Based on the DPs turned last year, we'd expect to have 38 thus far, rather than the 25 actually received. Using the 2007 splits, we can divide the expected 38 up by position, to predict a number of double-plays for each position, and then compare that to the actual which have been started there:

Pos	Exp	Act	Diff
2B	13	10	-3
SS	11	6	-5
3B	9	5	-4
P	3	3	0
1B	2	1	-1

This suggests that while there have been fewer almost all around the diamond, the double-plays which aren't being turned, are mostly missing from the left-hand side of the infield.

It's hard to say if this is just some kind of statistical quirk over the first quarter of the season. It may be that this is partly tied to Arizona's impressive DER, because a double-play presumably only counts as one for DER purposes. I note that Pittsburgh, who lead the majors in double-plays, have the worst DER in the NL. On the other hand, Cincinnati, second-worst there, have second-fewest double-plays too, so I am wary of drawing any conclusions in this area. Certainly, it's something worth monitoring as we go forward.

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Dirty, off-the-cuff, roughshod explanation for the lack of double plays

Year – WHIP – K/9 – DP
2008 – 1.23 – 7.32 – 92??
2007 – 1.38 – 6.8 – 138
2006 – 1.40 – 6.87 – 139
2005 – 1.45 – 6.41 – 141

In short, the more bats you miss and the more runners you allow on base, the more ground balls you’re going to turn. It also doesn’t help that our pitching staff only generates 43% of its outs via the ground ball – fifth lowest in the NL.

Of course, to truly delve into a topic like this you need to look further into play by play data. To determine if the lack of ground balls is the fault of the pitching staff or the defense you need to look at ground balls turned as a percentage of the total number of ground balls induced with a runner on first. From just a cursory look through of the numbers, I’m inclined to think that the cause of this is a combination of small sample size, pitchers throwing fewer ground balls and having fewer runners on base to be doubled off.

by dahlian on May 19, 2008 11:41 PM EDT 0 recs

This "method" also accounts for

the disparity between Double D’s double play total and B-Webb’s total last year:

Pitcher – WHIP – K/9 – DP/AB
Webb – 1.189 – 7.39 – 44.2
Davis – 1.588 – 8.72 – 32.6

And Davis is widely considered to be a fly ball pitcher. At least he showed the ability to use his curveball to generate ground balls when needed. Those times usually being after he walked a couple batters.

by dahlian on May 20, 2008 12:26 AM EDT up 0 recs

Well

I thought they spoke of Haren as a “fly ball pitcher” before this year as well, yet he’s done a pretty good job of keeping the ball in the park so far. Do you think most pitchers are able to really adapt like that?

Max Scherzer is all out of bubblegum.

by DbacksSkins on May 20, 2008 1:03 AM EDT up 0 recs

really interesting stuff, Jim

Thanks for the leg work. Dahlian already stole one of my three possible explanations: the fact that our staff has a better K rate this year. Another reason might be the fact that this year’s staff is allowing fewer baserunners, resulting in fewer possibilities to turn the twin killing. A third possibility is the extended absence of Hudson. Even though there are only 3 fewer DPs turned by hits to 2B, the 2B would be the one relaying the throw from all hits to SS and 3B.

"There are only two seasons: winter and baseball"
-- Bill Veeck

by njjohn on May 20, 2008 7:17 AM EDT 0 recs

Interesting

Nice work, Jim – I think the final sentence is the best, that this is mainly something worth monitoring as the season rolls on.

There are clearly lots of things that go into double plays, but it’s fairly established that having a subpar pitching staff is the thing that will have the biggest effect on the gross number of DPs. It’s pretty routine for teams that give up a high opponent OBP to just frankly be in more defensive potential DP situations – so i don’t think the total DPs in a season is all that worthy of a stat.

You’re correct to look at rates, but there are a couple of issues there as well – one, I think the first thing to look at is DP per potential DP situations. I don’t think DPs per AB or per PA for a pitcher are really all that meaningful – I would guess that the primary thing causing Doug Davis to have a high higher DP per AB rate (or lower AB per DP rate as you have listed it) is that Doug Davis, especially last year, gave up more baserunners than Mr. Webb.

Also – if we’re looking at DPs per DP situation rates, we need to identify it as situations with a runner on first and fewer than 2 outs, not just times when there is a runner on first. So we take those situations, look at the DP percentage of this year v. last year and see if there’s a difference. I like the suggestion by dahlian that you could also look at the DPs turned per Ground balls induced in DP situations stats – that would be a good stab at figuring out how much is due to fielding problems and how much is due to a lack of ground balls by the pitchers. It would, of course, be subject to the usual problem with defensive stats (e.g., was a groundball not fielded because of fielder performance or because the pitcher let him hit it too hard?).

I do think that if you really crunched this stats-wise you would see that at least some component of this is due to chance. I don’t think the conclusion that “it’s the left side of the infield” is a valid one; you’re comparing -1 and -3 to -4 and -5, and I doubt with only a fourth of the season gone by that those deficits are significantly different. You’re also basing those expectations and subsequent deficits on a distribution stats that already attribute 53% of double plays to the left side of the infield. I think that’s at least somewhat circular, something like “the left side of the infield tends to turn the most double plays, so if double plays are down, it must be the fault of the left side of the infield.” Which is something of a truism – so what this is really shows is that DPs are down, and they are down more in the positions that bear a larger burden of the double play task. A loosely related example would be that if the team strikeouts were down and you attributed it primarily to the starters (who throw more innings and have a disproportionate effect on K totals).

Again, cool work – I don’t mean to be overly critical, and I really enjoy the smart stat analysis that goes on here. I also like what njjohn points out, that multiple players are involved in every double play, so the SS and 2b are going to effect your turn rates regardless of who “starts” the double play.

by nyetjones on May 20, 2008 12:07 PM EDT 0 recs

I wish there were a DP report for pitchers

They have one for hitters at BP, but not pitchers. What I did though was check the BR/9 and GB% to at least get a sense of possible DP opportunities. Obviously the teams putting more guys on base have more opportunities to get DP’s, but you also have to see if the pitchers are inducing a lot of GB’s. Although it’s not perfect, I think it’s safe to say that pitching staffs that allow a lot of baserunners, AND induce a lot of groundballs, are giving their infielders more opportunities to turn DP’s.

Baserunners/9 IP
AZ 11.56
CH 11.75
AT 11.98
SL 12.26
SD 12.62
NY 12.80
LA 12.86
PH 12.90
HO 13.20
FL 13.25
CI 13.29
WA 13.40
SF 13.55
CO 13.59
MI 13.89
PI 14.52

GB%
AT 60.7
CO 60.2
PH 59.2
WA 57.7
LA 57.6
SL 57.2
PI 56.8
AZ 56.2
SD 55.9
MI 55.4
HO 54.9
NY 54.4
CH 53.9
CI 53.5
FL 51.3
SF 48.3

GB Double Plays per 9
PI 1.02
SD .88
Co .88
Mi .82
PH .81
HO .80
LA .74
AT .71
FL .70
SF .70
CH .64
SL .62
AZ .57
CI .57
NY .56
WA .55

As a team, the D backs GB% and GB/FB ratios are both middle of the pack, ranking 8th in the NL, while at the same time they have allowed a league LOW Baserunners per 9 IP

That combination has certainly led to fewer DP opportunities for D Backs infielders.

The Pirates, Padres, and Rockies are the top 3 teams in double plays turned per 9 innings. The Pirates have the most BR/9 allowed in the NL, and the Rockies have the 3rd most BR/9 allowed and the 2nd highest GB%. So you would expect those two teams to be at the top of the DP’s turned list.

The Padres are the interesting team here, as they rank 2nd in DP’s turned, but have the 5th best BR/9 and are just 9th in GB%. They are REALLY making the most of their DP opportunities.

by shoewizard on May 20, 2008 1:51 PM EDT up 0 recs

Oh, forgot to compare the 2007 Data fro AZ

BR/9
2007 12.82, (7th) 2008 11.56 (1st)

GB%
2007 55.3%,(8th) 2008 56.2% (8th)

K/9 %
2007 6.8 (9th) 2008 7.32 (3rd)

DP/9
2007 0.86 (4th) 2008 0.57 (13th)

So…....

Most likely the reduced rate is due in large part to fewer baserunners in the first place, and also more strikeouts, and therefore fewer balls in play. There are probably some missed opportunities in there as well. Anecdotally, I’d say from watching the games, there are probably at least 3-5 times I thought they definitely should have turned a DP and didn’t. But overall, it seems pretty clear there have far fewer chances to roll up DP’s

Going from Livan Hernandez and his 1.6 WHIP, to Dan Haren, the NL leader in WHIP, (0.977) will do that for a staff. ;)

by shoewizard on May 20, 2008 2:06 PM EDT up 0 recs

Much appreciated

This was only intended as a vague scratching of the surface; while looking at shoe’s DER rate, I noticed that our double-play rate was WAY down and it piqued my interest. It is a VERY complex topic, because a double-play will typically involve contributions from five players: the pitcher, who throws the ball, the hitter who produces the ground-ball [and whose speed also affects the chances of a double-play being turned] and the three fielders who typically are involved in executing the actual play. Indeed, you could conceivably add in the hitting team’s manager, who has the option to send the runner to try and stay out of the twin killing. All of these have (more or less) significant input on whether a double-play is turned – trying to separate out who is responsible for what, would be the work of…well, let’s just say, FAR more than an off-day! :-)

No doubt, some of this is certainly due to random fluctuation, and this makes it hard to slice the data up and still keep it meaningful. But we’d be expecting 50% more double-plays than we’ve actually turned, based on the past three years. As noted by several people, the swap of Hernandez for Haren is certainly significant, and the basic “fewer baserunners = fewer double-plays” is likely a big factor.

With regard to the specific positions, if you prefer percentages, the fraction attributed to 2B has actually increased from 35 to 40%, in contrast to the SS, which has declined from 30% to 24%. The numbers have dropped all over the diamond, but those started by the left-side appear to have dropped more than would be expected. More than can be attributed by chance? Probably not, though this doesn’t mean there isn’t a real effect involved.

It’s certainly something that could bear a great deal more analysis, but I doubt I’ll have much chance to look at it in any additional details, this side of the All-Star break! Happy to have shed even a flickering and weak light in the direction of this topic though.

by Jim McLennan on May 20, 2008 4:40 PM EDT up 0 recs

Also

Speaking of DPs – Pudge’s play on Hudson the other night, though painful for our side, was pretty smart. I wonder why more players don’t drop line drives and/or let infield flies drop, just to see if the ensuing mayhem could get another out. I feel like you could also do this to erase speedy baserunners when warranted, too.

by nyetjones on May 20, 2008 12:09 PM EDT 0 recs

Good Point

This same thought occurred to me during Webb’s complete game against the Phillies a few weeks back. BoMel gave him one more batter to get two outs, the ball was lined directly back to Webb who dropped it and then initiated a 1-4-3 double play. Looking at the play, it appeared that Webb did not intend to drop the ball but it certainly led to a better result once he did.

by UofAZGrad on May 20, 2008 1:48 PM EDT 0 recs