Strikeouts, Stabilization and Surprising Swings

You’ll hear us talk about statistical stabilization here, and link to pieces like Russell Carleton’s or Derek Carty’s. The basic idea is that there are thresholds at which a stat moves into a decent sample and becomes more meaningful.

Maybe you’ll come away thinking that we’ve said that ‘x stat is stable so that’s what you’ll get the rest of the way,’ and if so, that’s on us. That’s not what stabilization means in this context.

What it means is that the r-squared number that correlates a player’s past stats with his future stats in that category has passed .50. That’s a mouthful, here’s another try: if you were to try and predict future work in a category, you’d regress their current work against the league average. At the stabilization point, you can use half their own number plus half the league average in your calculations.

One more try, in the most colloquial language possible: Stabilization is the point at which a number in a category tells us more about their future work than the league average.

If that gets boiled down to more simple language, you can understand why. None of the above makes for hit monster posts.

But, there’s a little more to it: we play fantasy baseball. We don’t have the same stakes as a major league team, and if we’re in a redraft league, we have to move faster than the numbers, in effect. For example, power doesn’t stabilize until 550 plate appearances or so. There’s no way we can hold on to someone experiencing a power blackout for a full season in your standard 15-team redraft.

And so we simplify our language, at the cost of precision. “Time to worry about this player’s production because of this stat has stabilized” is something I’ll say. I understand it’s more complicated than that. I understand that shivers will go down spines. But I have moves to make on my fantasy teams, and I need to grasp at straws sometimes.

All of that is pre-amble. According to Derek Carty’s excellent piece linked above, strikeout rate for batters has stabilized for most regulars. Because we’re shaving the garlic here anyway, I’ve set the minimum at 90 plate appearances instead of the 100 he found. And I’ve set their current strikeout rate against last year’s, so that you can sort the table in different directions.

I’ll post the table at the bottom, after we point out some interesting movers and shakers. Strikeouts are negatively correlated to batting average, so that’s why you care about this. Even though most researchers and baseball people don’t care about batting average and might cringe at using stabilization this way, we have categories to protect. We must move quickly.

I’m picking up what Miguel Montero is laying down. Swing metrics are ahead of per-PA metrics, and he’s swinging less than he’s ever had, he’s reaching less than he’s ever had, and he’s making more contact than he’s ever made. At this strikeout rate, there’s plenty of room for regression while still showing batting average improvement. Monter’s hit .280+ in three of his five big-sample years, and I think he’ll do that again this year.

Brandon Moss isn’t seeing the same kind of radical changes in his swing profile, but the contact is up and the strikeout rate is down. This is interesting because he’s made more contact in the past, but seemed to go with the Big Swing for the Big Power. His owners own him for the power, so I’m a little more ambivalent about this big change.

Yoenis Cespedes is swinging less, reaching less, and making more per-pitch contact, so I’m buying this new contact rate. It’s not statistically important, but it’s nice to see it come with a better walk rate and comments from the player himself about shortening his swing. Since BABIP is hiding the fact that he’s improved, he makes for a decent buy-low, actually.

I love Jason Kipnis, still do.

Pedro Alvarez! God of Whiffs! What will we do if you change so fundamentally? We will go buy you. Because you have decided to swing less, reach less, and make more contact. And you haven’t cost your power. And you’re walking more. If only your batting average on balls in play (.161) loved you as much as I do right now.

On the other side of the spectrum, we’ve talked about Brad Miller enough, and it all looks bad. Every day makes him more droppable. Edwin Encarnacion, though, is getting a pass. But maybe he shouldn’t. At least, it doesn’t look like he’ll have his customary great strikeout rate this year. But it’s a testament to how good his strikeout rate used to be that he can fall this far and still have something close to an average strikeout rate. If the wrist is fine, I’m only slightly worried, because he can still provide a ton of value even with a worse batting average.

Norichika Aoki and Garrett Jones are both older gentlemen with flawed games. At their current rates, they’re playing themselves out of mixed league relevance quickly.

The next two are more important to more of yous. Mike Trout is probably unassailable, and it’s worth noticing that most of his swing rates are fine, it’s just a little drop in contact rate. This might need more attention. But there is reason to worry about Martin Prado. His swing rates are unchanged, but his ability to make contact outside the zone — not a skill that ages well — dropped seven points. That’s how you turn a small change in contact rate into a huge change in strikeout rate. Given his career strikeout rate is 10.6%, and he’s at 17% now, even with regression, we’re likely looking at Prado’s worst year for strikeouts. And his game is built on contact.

We’ll try to look into the rest of these guys, but here’s a sortable table that you can use for yourself:

Name	PA	K%	2013K%	14K-13K%	BABIP	AVG
Miguel Montero	105	8.6%	23.2%	-14.6%	0.273	0.271
Brandon Moss	96	18.8%	27.7%	-8.9%	0.295	0.268
Yoenis Cespedes	95	15.8%	23.9%	-8.1%	0.242	0.238
Jason Kipnis	107	14.0%	21.7%	-7.7%	0.264	0.247
Pedro Alvarez	107	23.4%	30.3%	-6.9%	0.161	0.172
James Loney	97	6.2%	12.9%	-6.7%	0.316	0.306
Matt Adams	98	18.4%	25.1%	-6.7%	0.408	0.337
Alex Gordon	101	13.9%	20.1%	-6.2%	0.313	0.277
Emilio Bonifacio	99	16.2%	22.3%	-6.1%	0.405	0.333
Mike Napoli	106	26.4%	32.4%	-6.0%	0.390	0.304
B.J. Upton	100	28.0%	33.9%	-5.9%	0.295	0.211
Carlos Gonzalez	101	21.8%	27.1%	-5.3%	0.265	0.234
Starlin Castro	100	13.0%	18.3%	-5.3%	0.304	0.292
Justin Morneau	97	12.4%	17.3%	-4.9%	0.360	0.356
Jose Altuve	116	7.8%	12.6%	-4.8%	0.309	0.292
Chase Utley	99	10.1%	14.9%	-4.8%	0.377	0.360
Jhonny Peralta	93	17.2%	21.9%	-4.7%	0.167	0.195
Ben Zobrist	114	8.8%	13.0%	-4.2%	0.321	0.313
Albert Pujols	110	8.2%	12.4%	-4.2%	0.244	0.290
Alfonso Soriano	101	20.8%	24.9%	-4.1%	0.286	0.258
Aramis Ramirez	102	11.8%	15.7%	-3.9%	0.288	0.280
Neil Walker	111	11.7%	15.4%	-3.7%	0.217	0.235
Prince Fielder	109	12.8%	16.4%	-3.6%	0.227	0.209
Troy Tulowitzki	98	13.3%	16.6%	-3.3%	0.349	0.342
Asdrubal Cabrera	100	17.0%	20.3%	-3.3%	0.250	0.211
Jed Lowrie	114	10.5%	13.7%	-3.2%	0.316	0.292
Evan Longoria	109	20.2%	23.4%	-3.2%	0.351	0.296
Michael Brantley	102	7.8%	11.0%	-3.2%	0.253	0.264
Jay Bruce	103	23.3%	26.5%	-3.2%	0.271	0.224
Anthony Rendon	112	14.3%	17.5%	-3.2%	0.326	0.298
Adam LaRoche	104	19.2%	22.2%	-3.0%	0.359	0.307
Chris Davis	94	26.6%	29.6%	-3.0%	0.333	0.250
Hunter Pence	109	13.8%	16.7%	-2.9%	0.282	0.253
Alejandro De Aza	90	18.9%	21.8%	-2.9%	0.190	0.183
Ryan Howard	107	27.1%	30.0%	-2.9%	0.295	0.245
Yasiel Puig	96	19.8%	22.5%	-2.7%	0.311	0.265
Trevor Plouffe	105	19.0%	21.5%	-2.5%	0.388	0.310
Freddie Freeman	107	16.8%	19.2%	-2.4%	0.371	0.344
Alex Rios	107	14.0%	16.3%	-2.3%	0.376	0.330
Todd Frazier	97	18.6%	20.8%	-2.2%	0.266	0.244
Eric Hosmer	104	12.5%	14.7%	-2.2%	0.341	0.295
Nolan Arenado	109	11.9%	14.0%	-2.1%	0.303	0.298
Anthony Rizzo	104	16.3%	18.4%	-2.1%	0.319	0.284
Nelson Cruz	101	21.8%	23.9%	-2.1%	0.305	0.284
Nick Markakis	111	9.0%	10.9%	-1.9%	0.330	0.300
Dan Uggla	93	30.1%	31.8%	-1.7%	0.281	0.209
Ian Kinsler	96	8.3%	9.6%	-1.3%	0.284	0.278
Allen Craig	103	16.5%	17.8%	-1.3%	0.203	0.177
Elvis Andrus	110	12.7%	13.9%	-1.2%	0.284	0.253
Domonic Brown	101	16.8%	18.0%	-1.2%	0.311	0.264
Joey Votto	112	17.9%	19.0%	-1.1%	0.328	0.287
Dustin Pedroia	115	9.6%	10.4%	-0.8%	0.305	0.274
Jean Segura	94	12.8%	13.5%	-0.7%	0.267	0.239
Jimmy Rollins	102	13.7%	14.0%	-0.3%	0.280	0.261
Chris Carter	92	35.9%	36.2%	-0.3%	0.238	0.169
Matt Holliday	107	14.0%	14.3%	-0.3%	0.312	0.272
Howie Kendrick	111	17.1%	17.3%	-0.2%	0.354	0.300
David Ortiz	103	14.6%	14.7%	-0.1%	0.250	0.253
Yonder Alonso	97	12.4%	12.5%	-0.1%	0.198	0.174
Alexei Ramirez	109	10.1%	10.1%	0.0%	0.360	0.350
Omar Infante	97	9.3%	9.2%	0.1%	0.289	0.279
Paul Goldschmidt	124	21.0%	20.4%	0.6%	0.369	0.306
Jonathan Lucroy	95	12.6%	11.9%	0.7%	0.347	0.306
Giancarlo Stanton	112	28.6%	27.8%	0.8%	0.328	0.270
Daniel Murphy	104	14.4%	13.6%	0.8%	0.337	0.289
Jayson Werth	111	19.8%	19.0%	0.8%	0.338	0.281
Yunel Escobar	97	13.4%	12.6%	0.8%	0.253	0.225
Leonys Martin	93	21.5%	20.5%	1.0%	0.400	0.309
Jacoby Ellsbury	103	15.5%	14.5%	1.0%	0.372	0.312
Gerardo Parra	118	16.1%	15.1%	1.0%	0.292	0.250
Dexter Fowler	94	22.3%	21.3%	1.0%	0.295	0.238
Jose Bautista	112	17.0%	15.9%	1.1%	0.305	0.294
Brett Gardner	91	22.0%	20.9%	1.1%	0.350	0.272
Robinson Cano	102	13.7%	12.5%	1.2%	0.342	0.301
Jason Castro	90	27.8%	26.5%	1.3%	0.265	0.221
Salvador Perez	97	13.4%	12.0%	1.4%	0.270	0.239
Erick Aybar	94	11.7%	10.0%	1.7%	0.286	0.261
Andrew McCutchen	120	16.7%	15.0%	1.7%	0.320	0.286
Alberto Callaspo	91	11.0%	9.1%	1.9%	0.279	0.272
Josh Donaldson	119	18.5%	16.5%	2.0%	0.291	0.278
Carlos Gomez	112	26.8%	24.7%	2.1%	0.373	0.297
Adeiny Hechavarria	101	18.8%	16.6%	2.2%	0.329	0.269
Wil Myers	101	26.7%	24.4%	2.3%	0.306	0.231
Juan Uribe	103	21.4%	19.0%	2.4%	0.360	0.310
Yadier Molina	95	12.6%	10.2%	2.4%	0.368	0.344
Buster Posey	91	14.3%	11.8%	2.5%	0.226	0.238
Hanley Ramirez	105	18.1%	15.5%	2.6%	0.324	0.280
Ben Revere	96	13.5%	10.7%	2.8%	0.363	0.312
Nick Swisher	113	24.8%	21.8%	3.0%	0.278	0.218
Miguel Cabrera	91	17.6%	14.4%	3.2%	0.299	0.259
Angel Pagan	100	15.0%	11.8%	3.2%	0.385	0.333
Carlos Santana	103	20.4%	17.1%	3.3%	0.150	0.122
Justin Smoak	92	26.1%	22.8%	3.3%	0.298	0.241
Billy Butler	102	18.6%	15.3%	3.3%	0.257	0.209
Carlos Beltran	98	18.4%	15.0%	3.4%	0.290	0.275
Colby Rasmus	91	33.0%	29.5%	3.5%	0.235	0.188
Adam Jones	103	23.3%	19.7%	3.6%	0.338	0.265
Melky Cabrera	117	16.2%	12.6%	3.6%	0.382	0.345
Brian Dozier	113	23.0%	19.3%	3.7%	0.217	0.217
Matt Dominguez	94	20.2%	16.3%	3.9%	0.234	0.221
Brett Lawrie	103	19.4%	15.4%	4.0%	0.157	0.179
Desmond Jennings	95	23.2%	19.1%	4.1%	0.357	0.269
Bryce Harper	91	23.1%	18.9%	4.2%	0.377	0.289
Kyle Seager	91	22.0%	17.6%	4.4%	0.241	0.228
Marlon Byrd	102	29.4%	24.9%	4.5%	0.385	0.278
Chris Johnson	92	26.1%	21.2%	4.9%	0.317	0.241
Joe Mauer	111	23.4%	17.5%	5.9%	0.358	0.266
Jedd Gyorko	101	29.7%	23.4%	6.3%	0.197	0.144
Will Venable	92	29.3%	22.9%	6.4%	0.295	0.205
Justin Upton	101	31.7%	25.0%	6.7%	0.440	0.330
Adrian Gonzalez	109	22.0%	15.3%	6.7%	0.333	0.313
Jason Heyward	107	23.4%	16.6%	6.8%	0.239	0.191
Aaron Hill	118	20.3%	13.3%	7.0%	0.310	0.255
Starling Marte	117	31.6%	24.4%	7.2%	0.343	0.229
Matt Carpenter	114	21.1%	13.7%	7.4%	0.356	0.281
Pablo Sandoval	99	21.2%	13.5%	7.7%	0.212	0.180
Eric Young	106	24.5%	16.7%	7.8%	0.302	0.216
David Wright	113	23.9%	16.1%	7.8%	0.355	0.275
Brandon Belt	104	29.8%	21.9%	7.9%	0.311	0.263
Everth Cabrera	109	23.9%	15.9%	8.0%	0.403	0.301
Ian Desmond	109	30.3%	22.1%	8.2%	0.313	0.243
Brandon Phillips	107	23.4%	14.7%	8.7%	0.338	0.262
Mike Trout	111	27.9%	19.0%	8.9%	0.413	0.320
Martin Prado	112	17.0%	8.0%	9.0%	0.284	0.234
Garrett Jones	102	32.4%	23.0%	9.4%	0.316	0.237
Norichika Aoki	102	15.7%	5.9%	9.8%	0.333	0.277
Brad Miller	90	28.9%	15.5%	13.4%	0.211	0.174
Edwin Encarnacion	107	23.4%	10.0%	13.4%	0.319	0.242