Justin Verlander's Declining BABIP

Justin Verlander may be the best pitcher on the planet at the moment. He won the AL Cy Young and MVP, last season. Last week, he was picked 4^th overall in ESPN’s Franchise Player Draft, despite his age, 29. He currently leads all pitchers in fWAR (2.7). Surprisingly last year, he finished with only the third best fWAR (7.0) in his award winning campaign. So where did this difference come from? How did baseball’s third best pitcher by possibly the most telling metric, end up with a CY Young and MVP trophy in his closet?

For the moment, let’s forget that voters still take pitching wins into serious consideration for both those awards, as Verlander won 24 games in 2011. The real elephant in the room for Verlander was not wins, but instead that nasty BABIP, who seems to come up in every conversation lately. Verlander finished last season with the second-lowest BABIP (.236) among qualified starters, behind only Tampa Bay’s Jeremy Hellickson. This incredibly low BABIP caused many writers to become concerned with the sustainability of Verlander’s success for his 2012 campaign.

This March, esteemed baseball writers, Tom Verducci and Rob Neyer, both wrote stories, for SI and SBnation respectively, about Verlander's BABIP. When asked about his low-BABIP, Verlander gave the typical response to questions on whether or not he'll be able to sustain this type of success; stating that he "learned to pitch", "hold back his best velocity to later innings", "not leaving pitches (pitches) where a hitter can barrel them up", "pitching to soft contact", and "maintain his stuff as games went on".

Verducci concluded without really concluding. Deciding to wait and see if Verlander could keep his BABIP low instead of just assuming it would rise back to his career average. Verducci made a great point that the bad infield defense behind Verlander, especially on the left side may not hurt him as much as one would expect, because Verlander hardly gives up grounders, and a very small percentage of them go to the left-side.

Neyer did not agree with the "wait and see" conclusion that Verducci made, stating that "Verlander's BABIP would take a hard turn towards his .285, career mark.

Thus, I beg to question whether Verlander has learned to pitch to softer contact and keep his BABIP lower than average, or if 2011 was, in fact, just a fluke.

Far too often, I think, people look at a pitcher with a low-BABIP, and just write those results off as "lucky", and automatically assume his numbers (ERA) will regress negatively. More often than not this is a fairly smart conclusion, but not in all cases. Pitchers like Johan Santana, Matt Cain, Ted Lilly, Barry Zito, Pedro Martinez, and Greg Maddux have shown that it's possible to put up consistently low BABIP's during their prime, and for a good portion of their careers. Pitchers who have shown that pitchers have some control over balls in play make the analysis of a low-BABIP a much more complicated task.

We all know by now that year-to-year BABIP's have extremely low correlations; there's a large amount of volatility in BABIP's before they stabilize. The Book says that BABIP stabilizes for pitchers after six or seven years and Baseball Propectus has it at 8 years. 2012 will be Verlander's 7th full season as a starter. So at first glance it seems easy to say that his career BABIP has yet to stabilize, or will after this season; thus, his .236 mark would be clearly a fluke. But, BP’s 8 years to stablize is misleading, as it assumes 650 BF per season. Over the first five full seasons of Verlander’s career he averaged 886 BF per season. BP's Derek Carty showed that BABIP stabilizes after 3,729 BF.

By this number, Verlander's BABIP stabilized after his seventh start of the 2010 season, a win against the Cleveland Indians on May 8^th (interestingly enough that start was a rare "classic" quality start 6 IP 3 ER). His career BABIP was .298 about league average (.297 from '06-'09) up to that point. Verlander being a true-talent average BABIP was a little surprising because of his career K-rate (9.00) and ground-ball rate (39.6%) at that point. Matt Swartz has shown that high strikeout and low ground-ball pitchers induce weaker contact,; thus, yielding lower BABIP's.

From Verlander's pro-debut to that start in 2010, it is safe to conclude that Verlander's .298 BABIP was a reflection of his true talent. The Tigers' flamethrower thinks, though, that he has increased his ability to pitch to softer contact, and reduce his BABIP, since that date. Verducci's piece noted that something clicked for Justin in his no-hitter in early 2011. So what has Verlander's BABIP been since May 8th, 2010?

The answer: .256.

Usually the first argument against a low-BABIP is that the pitcher had above-average defense playing behind him, and the opposite for a pitcher with a high-BABIP; bad defense. Thus, the first question that needs to be asked is whether or not the Tigers' defense from 2006 to 2009** was, in fact, worse than it has been from 2010-the present.

The Tigers' defense and pitching staff BABIP has actually gotten worse since 2009.

	BABIP		Defense
Year	League	Team (Rank)	UZR (Rank)
06-09	0.297	.293 (22nd)	31.7 (13th)
10-12	0.291	.297 (9th)	-3.7 (14th)

**Note**-- 19% of Verlander's 2010 fell under the first 3729 PA or stabilized data set; while, the rest is in the post-stablized. So, I grouped 2010 defensive data for league-average BABIP, BABIP for the Tigers, and the Tigers' defense rankings into the post-stablized set.

Offense has been down since 2010; thus, BABIP's have dropped across the league, but the Tigers' team BABIP has moved in the opposite direction. The recent change in the hitting environment would lead to a lower BABIP for Verlander, if all other things were equal. But the fact that the Tigers' defense has gotten worse most likely offsets that decrease. Thus far in 2012, the Tigers have the second worst defense in baseball in terms of UZR (-11.8), and third highest staff BABIP (.313), but Verlander has been able to post a .255 BABIP despite this.

So if a defensive improvement didn't cause Verlander's BABIP to drop, what did?

Earlier I noted that there was a good deal of evidence to show that pitchers with high strikeouts and low ground-ball rates ten to have lower BABIP. Verlander was an average BABIP pitcher before, despite having high K-rates and giving up few ground-balls. Since May 8th, 2010, Verlander's strikeout rate hasn't improved and he hasn't given up any fewer ground balls. His strikeout rate has actually decreased and ground ball rate has increased; though, by negligible amounts.

Verlander	BABIP	K/9	GB%
Pre-Stable	0.298	9.0	39.6
Post	0.256	8.9	40.3

It's possible that Verlander bucked the trend before and has finally began to reap the benefits of being a high-K, low-GB pitcher, but that seems unlikely. It's hard for me to believe that little to no change in these metrics would lead to such a sharp drop in Verlander's BABIP.

With no real changes for Verlander in terms of K's and GB's, I looked for other changes in his statistics; which could have caused this large drop:

Verlander	BABIP	BB/9	LD%	FB%	IFFB%	HR/FB	ERA	xFIP	SIERA
Pre-Stable	.298	3.04	20.4	40.0	10.5	8.1	3.95	4.06	3.99
Post	.256	2.28	18.9	41.1	12.3	7.2	2.69	3.29	3.17

Verlander has improved his ability to suppress home runs, as well as, issue fewer free passes; which has lead to a drop in FIP, but isn't really relevant to his BABIP. Tom Tango showed that high walks and HR-rates usually lead to a lower BABIP, not the other way around. While there isn't evidence that combination of high K's, low BB's and low HR's leads to a high BABIP, there also isn't evidence to prove that it leads to a lower than average BABIP.

Intuitively a decrease in line drives, coupled with an increase in in-field fly-balls would lead to a lower BABIP, because line drives result in more hits, while in-field flies result in almost all cases in outs. Verlander's post stabilized 18.9% LD% is not extremely low, but it is below average, and his 12.3% IFFB% is also not extremely high, but again it is above-average. The assumption that low LD's and high IFFB's is just that though, an assumption. So I checked into the BABIP's of the top-30 pitchers with low LD%'s and top-30 pitchers with high IFFB's, over 3-year intervals, dating back to 2003. I used 3-year intervals because one-year BABIP's have so much variation. Only starters with400 IP (133.1 IP per season) over the 3-year span were included.

Below I listed the percentage of top-30 pitchers in low LD% and IFFB% with BABIP's below league average over the 3-year intervals. Also, I listed the percentages of pitchers who finished in the top-30 in both of those categories.

Min. 400 IP	LD%	IFFB%	Both % (#)
2009-2011	60.0%	76.7%	90.0% (10)
2006-2008	60.0%	73.3%	80.0% (15)
2003-2005	80.0%	73.3%	100.0% (10)

This data backs the assumption that low-LD, high IFFB pitchers tend to induce softer contact and have low-BABIP's. Verlander's recent combination of high K's, low GB's, low LD's and high IFFB's, may have caused his reduction in BABIP, but is SIERA still makes me a little uncertain that this is true.

Verlander has clearly been a better pitcher since May 8th, 2010. His xFIP and SIERA have both fallen by almost a point since that date. According to Swartz' research SIERA favors high-FB/high-K pitchers (like Verlander) more than xFIP does. The 12 point gap between his SIERA and xFIP reiterates this point. It seems to me that SiERA thinks that Verlander is able to limit his BABIP and HR/FB-rate, but probably not limit his BABIP to the extent that he has of late. SIERA and xFIP are both a great predictors of future ERA. The gap between Verlander's ERA and his SIERA and xFIP, in the post-stablized data, is rather large; which, would make me assume that his ERA will rise in the future.

My conclusion that SIERA thinks Verlander can't limit his BABIP to the extent that he has been, may be flawed though. A change in BABIP is not the only way to rectify the difference between his ERA and SIERA.

The post-stablilized data includes, of course, Verlander's Cy Young/MVP winning 2011 season. His .236 BABIP that year, is the main reason for not only this post, but also for Neyer and Verducci's pre-season pieces. However, Neyer's piece brought up a different aspect of his 2011 campaign that was almost definitely lucky, his left on-base percentage. In 2011, Verlander had the fifth-highest LOB% (80.3%) among starters, which is almost 8 points higher than his career LOB% (72.4%), excluding that season. A drop in LOB% would not make up the entire SIERA-ERA gap, but for sure, will have an effect on it, so it wouldn't be right to levy all the blame for that gap on BABIP's shoulders.

There was only one other change in Verlander's numbers that could possibly persuade me that his BABIP fell for a reason other than a stretch of good luck. The change came on pitches thrown outside of the strike zone.

These numbers come from Baseball Info. Solutions (for reference, since 2002 the average O-Swing% is 30% and O-Contact% is 68%):

Verlander	BABIP	O-Swing%	O-Contact %
Pre-Stable	0.298	25.2%	62.7%
Post	0.256	33.0%	69.0%

Batters have been swinging a good deal more of Verlander's pitches outside of the zone than they were earlier in his career, but have been making more contact on those pitches. Despite the increase in contact Verlander has been able to maintain his strikeout rate.

Excluding hitters like Vladimir Guerrero and Josh Hamilton, contact on pitches outside of the zone usually does not result in hits. However, an increase in O-Swings and contact reducing BABIP is just an assumption. The weaker contact that resulted from this change could be the reason for more pop-ups and fewer line-drives that Verlander induced; thus, I fear I may be double counting this as a reason for Verlander's reduction in BABIP.

More research into the correlation between high O-swing% and O-contact% and low BABIP is something I hope to look into for a future post. But these numbers could possibly explain Verlander's strange 2009 campaign. That season Verlander had the highest BABIP (.319) of his career, despite a career-low GB% (36) and his highest career K-rate(10.09). Based on Swartz' research these numbers would lead me to expect that Verlander would have a BABIP well below league average; instead, of a BABIP that was 26 points above it.

That season, Verlander had the lowest O-contact% (58.8%) of his career, leading to a lot of strikeouts, but not a lot of weak contact. He posted the lowest IFFB% (9.2%) of his career; which isn't a good number at all given his FB% rate (42.8%) . Also his LD% (21.2%) in 2009 was the 10th highest among qualified starters. It seems fairly reasonable to conclude Verlander was not able to induce weak contact that year; which could have been caused by many different factors, but it's possible it was due to his swing and miss ability on pitches outside of the zone.. Using IFFB% and LD% to conclude that he gave up harder than average contact, also may not be the best idea.

Until Hit f/x data is available to the public (if it ever is), it will continue to be difficult to analyze how strong of contact hitters actually make; thus, any speculation that Verlander, or any other pitcher, can actually suppress contact, cannot truly be proven. LD% has it flaws, as Colin Wyers has pointed out there is a fair amount of ambiguity and error in the classification of line drives in even, Baseball Info. Solutions very useful data.

It's possible that Verlander's BABIP has dropped because he embraced his inner conformist and has become a high-K/low-GB/low-BABIP pitcher.

It's possible that Verlander has "learned" to pitch to soft contact, and his low LD-rates and high IFFB%'s are the reason for a legitimate reduction in his BABIP.

It's possible that the reason behind the supposed softer contact that Verlander learned to pitch to, has come from contact on pitches swung at off the plate.

It's also very possible that his BABIP fell in large part due to the L-word, that everyone wanted to use to classify his 2011 season. Luck is still a huge possibility as the post-stabailized data set has not yet stabilized. Verlander is over 50% (55.37% to be exact) of the way to enough face enough batters to form a new stabilized BABIP data set.

It seems hard for me to believe that his BABIP will rise back to his original true talent level (.297), as it currently sits over 40 points below that number.

Verlander probably will never have a BABIP as low as it was in 2011, again. Verducci pointed out this fact out in his piece. But there's at least some reason to think that Verlander has become better than he was earlier in his career at suppressing hard contact, and yielding a lower than average BABIP.

However, we'll need to wait until at least after the 2013 season to be certain of the fact that he's actually become a sustainably low-BABIP pitcher.

All data comes courtesy of Fangraphs.

You can follow Glenn on twitter @Baseballs_Econ.