The 2016 xStats Most Improved Batters

Last week I wrote about this season’s top pitchers and batters according to xStats. The top players in each category weren’t especially controversial, Clayton Kershaw, Aroldis Chapman, and Mike Trout respectively for Starting Pitcher, Reliever, and Batter. You could perhaps debate Chapman, maybe you prefer Andrew Miller for instance, but generally these guys are universally regarded as the top in the game. This week I want to look at the most improved players. I am using the same weighted rank I used last week. It isn’t any sort of sophisticated weighting, it is more of a back of the envelope type estimation for how each of the associated stats relate to run scoring. I’m just giving xOBA and VH% 40% of the weight, xSLG, xBACON, and xOBP share the next 40%, and PH%, xAVG, and xBABIP share the remaining 20%. I feel this roughly represents each of their predictive power, relative to one another, but is gut feeling, these rankings are very subjective.

I’ve taken the 15 most improved batters from 2015 with at least 400 PA using according to the ranking I described above. Batters had to have as least 400 PA in both 2015 and 2016 in order to qualify.


Most Improved Batters In 2016
2015 2016 Rank
Name PA xBABIP xOBA VH% PH% Rank PA xBABIP xOBA VH% PH% Rank Increase
Jean Segura 584 .310 .288 4.5% 21.1% 151 687 .325 .363 8.9% 16.9% 20 131
Jose Altuve 689 .295 .323 5.7% 26.7% 134 716 .313 .385 9.5% 22.9% 25 109
Yasmany Tomas 426 .337 .290 5.4% 14.3% 127 563 .310 .365 10.7% 16.7% 16 111
Gregory Polanco 654 .303 .315 5.5% 20.8% 133 588 .325 .354 9.2% 16.7% 31 102
Addison Russell 525 .277 .276 5.7% 22.3% 165 590 .286 .342 7.8% 19.3% 83 82
Charlie Blackmon 685 .306 .323 5.8% 21.9% 121 632 .315 .366 9.0% 19.9% 28 93
Wilson Ramos 503 .303 .319 6.4% 20.3% 111 522 .308 .373 10.0% 19.2% 18 93
Neil Walker 603 .278 .313 5.3% 24.1% 155 458 .272 .359 8.7% 24.9% 73 82
Ian Desmond 640 .290 .289 7.0% 18.4% 142 674 .325 .335 7.9% 15.9% 58 84
Chris Carter 459 .242 .322 8.3% 19.2% 125 637 .273 .360 11.0% 17.1% 38 87
Yadier Molina 528 .301 .314 5.3% 27.1% 143 579 .322 .353 6.9% 21.2% 61 82
Victor Martinez 485 .285 .337 6.8% 27.0% 116 608 .306 .370 8.2% 19.7% 34 82
Mike Napoli 469 .237 .311 6.6% 22.6% 153 641 .248 .344 9.5% 19.7% 81 72
Daniel Murphy 538 .298 .353 8.6% 27.0% 70 579 .311 .401 10.4% 19.3% 7 63
DJ LeMahieu 622 .348 .332 5.5% 13.3% 69 634 .383 .394 7.6% 12.3% 10 59
Min 400PA, Ranks determined by a weighted ranking of xAVG, xOBP, xSLG, xBABIP, xBACON, xOBA, VH%, and PH%, putting emphasis on xOBA and VH%.

Jean Segura takes the cake.  Now, before the season, I very much doubt many people thought especially highly of him, at least outside of the Diamondbacks front office.  The trade to acquire him was met with a good deal of skepticism, with many questioning both his offensive and defensive capabilities.  However, during the course of the season he seemed to make it a priority to prove everyone wrong, and he put up easily the best season of his career.  Especially on the offensive side, where he became a legitimate threat.  He jumped up 131 ranks, from 151 to 20.  A very impressive and pretty surprising turn of events for the 26 year old shortstop.

The bottom of the list consist of two members of the top 10 batters club from last week: DJ LeMahieu and Daniel Murphy, which should make a good deal of sense, these guys leapfrogged from pretty good hitters up into the realm of elite/MVP. A tremendous achievement for both players. Some of these players are rebounding from injury plagued seasons, such as Victor Martinez, or establishing themselves after rookie campaigns, such as Addison Russell. However, many of these players have something in common, xStats undervalued their seasons last year, and seemingly overvalued them this season, so what could be going on here?

Lets look at Yasmany Tomas as an example. Last year he registered .290 xOBA and 5.4% Value Hits. This year he produced .365 xOBA and 10.7% Value Hits. He doubled his value hit rate and added 75 points to xOBA, going from a below average player to an elite bat, according to xStats. Looking at his wOBA, last year he hit .307 and this year .345. His wOBA has not shifted nearly as much as his xOBA, although in both cases he leaped from below average to above average, only to varying degrees.

I went into the data and compiled the following chart for Tomas, it denotes the number of batted balls he produced in a number of xOBA ranges.

Yasmany Tomas Number BIP In Given xOBA Ranges
2015 2016
Less than .088 61 20.5% 94 23.8%
Between .088 and .20 66 22.2% 70 17.7%
Between .20 and .30 39 13.1% 41 10.4%
Between .30 and .40 24 8.1% 25 6.3%
Between .40 and .50 13 4.4% 23 5.8%
Between .50 and .60 21 7.1% 23 5.8%
Between .60 and .70 16 5.4% 12 3.0%
Between .70 and .80 25 8.4% 23 5.8%
Between .80 and .90 11 3.7% 25 6.3%
Between .90 and 1.00 6 2.0% 10 2.5%
Between 1.00 and 1.10 6 2.0% 12 3.0%
Between 1.10 and 1.20 4 1.3% 4 1.0%
Greater than 1.20 5 1.7% 33 8.4%
Total 297 395

We already know roughly how many he has below .088, as that is the measure of PH%, although PH% is measured against plate appearances whereas here we’re going by balls in play, so the percents are a tad different. A lot of these side by side numbers are similar indeed with one huge exception, the greater than 1.2 group. A value of 1.2 is roughly equal to that of a double, so batted balls hit in that group are, on average, and this is including all of the balls caught for outs, equal to at least two bases. Those are exceptionally well hit balls. In 2016, Tomas produced more than six times as many of these super high quality batted balls. Yes, he had 140 extra plate appearances, but he produced 28 more of these balls. That is incredible.

Of these 33 high quality hits, 22 went for a home run, 1 triple, 6 doubles, 1 single, 2 fly outs and a line out. .909/909/3.152 slash line. Incredible, but again these are the best of the best contact he can produce so you would expect results like that.

In 2016 Tomas had a monster surge in high quality contact, along with a slight uptick in lower quality contact, whereas in 2015 he had much more mid range contact. So lets take a look at that 2015 mid range contact. He hit 99 balls that xStats categorized as having a value between .3 and .8 and I’ve detailed their results in the following table.

Yasmany Tomas 2015 Success On Mid Range Contact
Singles Doubles Triples Home Runs Slash Line
Actual 45 11 3 1 .606/.606/.808
xStats 47 8 1 1 .574/.574/.707

Batted balls in this range of values, between .3 and .8, are obviously pretty valuable contact in game. Not quite on par with the 1.2 value hits we looked at a moment ago, but these are still very good, roughly on par with what you may consider “line drive” contact when looking at the more traditional GB/LD/FB/PU stats you might be more used to seeing.  Anywho, xStats feels Tomas may have gotten a lucky on a few of the hits you see in this range, suggesting he may have lucked out in the form of three doubles and two triples.  Judging by Tomas’ foot speed, we can probably all agree its hard to believe he would hit three in a season without a little help from the defense.  I went through the more granular detail for these batted balls and pulled up five of what you might call his “lucky hits” from last year.

Yasmany Tomas’ Five “Lucky Hits”
Date Actual Result BIP% as 1B BIP% as 2B BIP% as 3B
08/11/15 Double 44.5% 3.4% 0.0%
09/11/15 Double 13.2% 18.7% 2.9%
07/29/15 Double 8.4% 23.0% 0.0%
06/17/15 Triple 82.5% 1.0% 0.9%
07/10/15 Triple 27.5% 24.9% 5.2%

These are his three least likely doubles and two least likely triples from last season. Two of these doubles have pretty high likelihoods, 18.7% and 23% respectively, and as such it might be unfair to call them “lucky” hits.  I mean, they had bout 1 in 5 chance for landing the way they did, those aren’t terrible odds.  However, that 0.9% triple is glaring right back at you.  That, well, lets just say Yasmany Tomas doesn’t have the speed to turn things into triples the normal way.  More likely, the defense made a mistake turning a single into a triple.   The 5.2% triple and 3.4% double are likely in the same category.

If you recalculate his wOBA for last season, subtracting the five hits xStats didn’t feel he deserved, it drops down to .291. In essence, the difference between his 2015 wOBA and 2015 xStats comes down to five batted balls.

You can agree or disagree with the logic xStats is using here, but this pretty much explains why his 2015 xOBA and wOBA differ by so much, what about his 2016 numbers? Well, his xStats suggest he deserved 6 extra singles, an extra double, and two extra triples.  Several of these “unlucky outs” are summarized below.  Each of these had better odds than a coin flip to land as a hit, but in Tomas’ case they were caught.  Sometimes life is cruel.

Yasmany Tomas’ Six “Unlucky Outs”
Date Actual Result BIP% as 1B BIP% as 2B BIP% as 3B
05/26/16 Lineout 83.0% 0.0% 0.0%
05/30/16 Lineout 78.3% 5.2% 0.9%
06/03/16 Lineout 67.3% 0.0% 0.0%
04/17/16 Lineout 66.1% 3.8% 1.7%
06/04/16 Lineout 63.2% 2.2% 0.0%
07/24/16 Lineout 53.7% 0.0% 0.0%

I think that’s just about all I can say about Yasmany Tomas at this time.  He may have gotten a tad lucky last year, it seems like this year his luck turned in the other direction.  You might be justified calling it statistical noise, but it does seem that he made a real, marked improvement this season in not only his in game production but also his quality of batted balls.  As I stated earlier, he leaped forward with 33 very high quality contact balls, up from 5 last season.  I’m not so sure you can luck into hitting the cover off the ball that many times, that seems like a genuine display of skill.  For each of the 15 batters on this list, I could do similar breakdowns as this showing that, perhaps, we’ve seen a real improvement on their ability.  Yes, some of what is going on here is statistical noise, but not all of it.  The batters you see above have had a pretty significant leaps in their performance.  How long they may carry this performance is another story.

We hoped you liked reading The 2016 xStats Most Improved Batters by Andrew Perpetua!

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Andrew Perpetua is the creator of and, and plays around with Statcast data for fun. Follow him on Twitter @AndrewPerpetua.

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Great stuff, Andrew. I’ve really enjoyed your work all year.

Regarding your last sentence, I realize there’s very little data but do you have any indication at all about the consistency of stats like VH% from year to year?