The Change: Ground Ball Rate Changers, More xBABIP

It was suggested that we should celebrate the day that stats stabilize. Today is Grounder Day! Eat a sloppy joe while sitting on a blanket. Drink one of these, or some of this, but I don’t know about having any of this. Grounder Day!

Well, we actually aren’t all the way there. Only about twenty players have officially reached the stabilization point for ground ball rate. But that’s fine. It actually serves as a reminder that stabilization is not something that magically happens at one point. Stabilization happens over a spectrum, and today we know a little more than we did yesterday, and tomorrow we’ll know a little more.

But! Relative to *other* stats on our leaderboards, we know a good deal about a player’s ground ball rate by now. And the beauty of that news is that just knowing a player’s change in ground ball rate can tell us a good deal about what sort of power we should expect from them going forward.

Of the 20 batters that reduced their grounder rate the most, only five currently have a lower isolated slugging percentage this year. Of the 20 batters that added the most grounders, only five have a higher isolated slugging percentage this year. And even though isolated slugging percentage is not stable for a while yet, this provides a good sanity check.

Top 20 Ground Ball Rate Droppers

Name	BABIP	Pull%	Hard%	ISO	GB%	15GB	Diff	ISO15	ISODiff
Daniel Murphy	0.425	38.4%	40.8%	0.229	26.4%	42.8%	-16.4%	0.168	0.061
Brett Lawrie	0.381	39.3%	29.2%	0.196	32.6%	48.8%	-16.2%	0.148	0.048
Salvador Perez	0.266	49.5%	30.3%	0.203	27.3%	41.9%	-14.6%	0.166	0.037
David Wright	0.344	35.4%	47.7%	0.183	23.1%	36.2%	-13.1%	0.145	0.038
Josh Donaldson	0.284	51.7%	43.2%	0.253	32.2%	44.8%	-12.6%	0.271	-0.018
Ben Zobrist	0.324	51.9%	30.6%	0.175	36.8%	49.0%	-12.2%	0.173	0.002
Nick Castellanos	0.400	40.8%	36.9%	0.258	25.2%	36.2%	-11.0%	0.164	0.094
Leonys Martin	0.254	44.9%	30.8%	0.165	40.8%	51.7%	-10.9%	0.094	0.071
Jason Heyward	0.303	39.0%	20.0%	0.039	46.5%	57.2%	-10.7%	0.146	-0.107
Joe Mauer	0.318	27.0%	34.2%	0.084	45.9%	55.7%	-9.8%	0.115	-0.031
Neil Walker	0.267	47.0%	36.0%	0.250	32.3%	41.8%	-9.5%	0.158	0.092
Starling Marte	0.415	38.5%	33.9%	0.153	44.4%	53.8%	-9.4%	0.157	-0.004
Yasmany Tomas	0.354	34.7%	43.6%	0.195	45.5%	54.9%	-9.4%	0.128	0.067
Robinson Cano	0.277	33.6%	32.8%	0.284	41.2%	50.5%	-9.3%	0.159	0.125
Austin Jackson	0.305	42.3%	36.1%	0.087	41.9%	51.1%	-9.2%	0.118	-0.031
Jonathan Lucroy	0.354	35.6%	31.7%	0.186	35.6%	44.7%	-9.1%	0.127	0.059
Yoenis Cespedes	0.280	41.5%	37.2%	0.361	33.0%	41.7%	-8.7%	0.251	0.110
Manny Machado	0.342	37.6%	38.4%	0.320	35.2%	43.7%	-8.5%	0.216	0.104
Ryan Howard	0.167	41.9%	46.0%	0.239	27.0%	35.5%	-8.5%	0.214	0.025
Carlos Santana	0.223	46.3%	33.3%	0.190	36.1%	44.5%	-8.4%	0.164	0.026

Minimum 150 plate appearances in 2015.

Daniel Murphy is the poster boy for this type of analysis. He’s a completely changed man, and the projection systems are going to miss that his batted ball mix isn’t the same any more. I keep waiting for the strikeout rate to surge based on the fact that he’s a pull fly ball guy now, but maybe his innate contact ability is making this package work for him. Take the over on his projected ten more homers, for sure.

This is a good list for practically anyone to be on. At least you know it is for Brett Lawrie, who’s enjoying a new approach in a new park more conducive to power. He might crack 20 this year. I’d take the over on his power projections, as I would with Salvador Perez, Ben Zobrist, Neil Walker, Robinson Cano, and Yoenis Cespedes.

Yasmany Tomas is a different player this year. His body is different, his mix is different, his plate approach… well, his mix is different. I’d give him that projected .270 batting average, but more like another 15 homers. You’ll look up at the end of the year and see him in the top ten for third basemen and if you’re me, you’ll snarf your beverage. I thought this guy wouldn’t play three years in baseball after I saw him last spring.

I’m not willing to declare everyone on this list an immediate buy. Leonys Martin, not sure he should hit more fly balls. Jason Heyward, maybe he should have a more even mix, because hitting more fly balls has only brought him to league average, and it doesn’t seem to be working. Ryan Howard, well. Because Ryan Howard.

But for most of these guys, this is good news.

Here’s the bad news list.

Top 20 Ground Ball Rate Adders

Name	BABIP	Pull%	Hard%	ISO	GB%	15GB	Diff	ISO15	ISODiff
Adrian Gonzalez	0.343	31.2%	28.4%	0.127	56.0%	37.3%	18.7%	0.205	-0.078
Gerardo Parra	0.341	30.8%	27.8%	0.166	60.0%	46.8%	13.2%	0.161	0.005
Jed Lowrie	0.354	39.4%	29.3%	0.043	47.5%	34.9%	12.6%	0.178	-0.135
David Freese	0.381	34.9%	37.2%	0.107	65.1%	54.4%	10.7%	0.163	-0.056
Adam Eaton	0.328	28.0%	27.3%	0.117	61.1%	50.7%	10.4%	0.144	-0.027
Curtis Granderson	0.227	45.6%	38.8%	0.207	41.2%	30.8%	10.4%	0.198	0.009
Randal Grichuk	0.253	46.6%	36.4%	0.183	47.7%	37.9%	9.8%	0.272	-0.089
J.D. Martinez	0.290	37.4%	36.5%	0.196	43.9%	34.2%	9.7%	0.253	-0.057
John Jaso	0.298	40.2%	21.5%	0.148	61.7%	52.7%	9.0%	0.173	-0.025
Lucas Duda	0.239	39.4%	34.3%	0.211	36.4%	27.4%	9.0%	0.242	-0.031
Nori Aoki	0.274	28.7%	13.0%	0.075	69.6%	60.7%	8.9%	0.093	-0.018
Chris Carter	0.275	42.9%	38.5%	0.338	38.5%	29.8%	8.7%	0.228	0.110
Denard Span	0.295	38.2%	24.3%	0.088	59.2%	50.5%	8.7%	0.130	-0.042
Marcus Semien	0.207	47.8%	29.4%	0.252	46.7%	38.1%	8.6%	0.147	0.105
Delino DeShields	0.288	36.4%	16.9%	0.085	55.6%	47.1%	8.5%	0.113	-0.028
Asdrubal Cabrera	0.340	50.9%	29.6%	0.104	44.3%	35.8%	8.5%	0.164	-0.060
Eric Hosmer	0.383	37.2%	34.5%	0.200	60.4%	52.0%	8.4%	0.162	0.038
Mark Teixeira	0.279	52.8%	30.3%	0.105	47.2%	38.8%	8.4%	0.293	-0.188
Alcides Escobar	0.307	35.3%	19.4%	0.050	55.9%	47.8%	8.1%	0.064	-0.014
J.T. Realmuto	0.356	39.6%	25.5%	0.121	52.8%	44.8%	8.0%	0.147	-0.026

Minimum 150 plate appearances in 2015.

This list should have age on it. Adrian Gonzalez, Curtis Granderson, John Jaso, Nori Aoki, Denard Span, Asdrubal Cabrera, Mark Teixeira, Jed Lowrie — welcome to the wrong side of the ground ball aging curve.

In some cases, there are mitigating factors. Jed Lowrie just told me yesterday that this was all part of adjusting to the shift and his new ballpark. You might expect some of his best batting average and OBP, but maybe only a full year pace of 8-10 homers. Denard Span admitted to me that April is his worst month (true) and that the offseason hip surgery was still in his mind, so maybe his mix will change a bit due to health.

But hey, there could be other health issues in here that we just don’t know about. But what do we do about the young, healthy guys? If they are Gerardo Parra or Adam Eaton, we shrug. So they’ll jack one or two fewer dongs? The world won’t notice, and the added batting average would offset any of that.

Here are the guys that should be worrisome beyond issues of age: Randal Grichuk, J.D. Martinez, Lucas Duda, and Eric Hosmer.

Grichuk is pairing a crazy pull rate with a bad grounder rate, and there’s no worse batted ball than the pulled ground ball. It’s nice that he’s cut the strikeout rate and upped the walk rate, but power is his game, and he needs to get some loft on the ball. He’s cuttable in mixed leagues.

You’ll hold on to the other three in mixed leagues, and maybe you’re scratching your head because Hosmer is doing just fine. Let this just serve as a reminder that players generally return to whence they came, and Hosmer has had high ground ball rates before. You may want to trade him a year early in keeper leagues rather than a year late.

Well maybe you won’t hold Lucas Duda in a batting average league, but don’t play the ‘try to catch a hot streak’ with him, you’ll just miss half of it. Play him against righties, and be happy with him in OBP leagues.

It’s Martinez that might have us the most nervous. That ground ball rate is approaching the spot it was in when he was not the good version of himself. He hasn’t gone all the way back… in this case, though, I’ll feel around in the dark for a strange opinion, perhaps: he’s made large changes to his batted ball mix in the past, he seems more ready to do it again than anyone else on this list.

We do have slightly better tools now, though, so let’s also run a few leaderboards from Andrew Perpetua’s great work using launch angles and exit velocity to predict BABIP and weighted on base average. Here are the 15 leaders and laggards in BABIP-xBABIP using his spreadsheet. The guys on top have been getting lucky, the guys on bottom have been unlucky.

Top 15 (and Bottom 15) in BABIP-xBABIP

First	PA	xBABIP	avg EV	vertical	16 BABIP	BABIP DIFF
Brett Lawrie	158	0.281	90.0	15.7	0.381	0.100
Jonathan Villar	154	0.312	89.2	1.5	0.411	0.099
Odubel Herrera	170	0.307	87.9	13.0	0.400	0.093
Dexter Fowler	156	0.340	90.0	11.2	0.429	0.089
Mark Reynolds	114	0.370	90.6	10.0	0.456	0.086
Nick Castellanos	143	0.315	89.1	19.1	0.400	0.085
David Wright	134	0.265	94.1	17.9	0.344	0.079
Mike Napoli	140	0.267	93.8	11.0	0.343	0.076
Martin Prado	146	0.329	87.1	6.6	0.402	0.073
Ryan Braun	143	0.323	91.9	8.8	0.396	0.073
Adam Duvall	116	0.292	89.8	15.5	0.364	0.072
Eric Hosmer	153	0.312	93.3	3.9	0.383	0.071
Travis Shaw	156	0.328	88.5	13.4	0.398	0.070
Chris Davis	155	0.243	90.3	17.7	0.312	0.069
Marcell Ozuna	153	0.304	91.2	9.0	0.370	0.066
Joe Mauer	158	0.375	89.8	6.1	0.318	-0.057
Yan Gomes	113	0.240	87.6	12.5	0.178	-0.062
Randal Grichuk	134	0.315	93.6	14.5	0.253	-0.062
Joey Votto	154	0.334	91.0	13.9	0.272	-0.062
Johnny Giavotella	101	0.310	89.6	9.1	0.247	-0.063
Chris Coghlan	120	0.254	88.4	9.8	0.189	-0.065
Mike Moustakas	105	0.291	92.8	11.8	0.225	-0.066
Derek Norris	120	0.298	92.4	13.3	0.228	-0.070
Prince Fielder	157	0.284	88.6	8.1	0.212	-0.072
Albert Pujols	162	0.265	91.1	9.7	0.192	-0.073
Jayson Werth	132	0.306	93.4	15.7	0.232	-0.074
Ryan Howard	123	0.242	93.9	17.9	0.167	-0.075
Nick Ahmed	144	0.285	88.1	10.0	0.204	-0.081
Ryan Goins	110	0.280	88.1	5.7	0.190	-0.090
Howie Kendrick	103	0.358	90.9	0.3	0.263	-0.095

SOURCE: Statcast

xBABIP calculated using launch angle and exit velocity buckets.

Lots of Brett Lawrie lessons today: don’t tape forties to your hands, watch your Red Bull intake, believe in the power, maybe, but not the batting average. There aren’t too many surprises, though, when you’re looking at .400 BABIPs. We haven’t seen many of those in the big leagues, and it’s an easy call. But some times you have to make sure you’re looking at the right column — Martin Prado and Ryan Braun will regress, and so will Travis Shaw, but not to the levels that we might have set in our heads. On the flip side, Yan Gomes might do better (he’ll have to, or be out of baseball), but also might only BABIP at .240 going forward.

The shift may complicate some things for Joey Votto, Prince Fielder, Ryan Howard, and even Albert Pujols, but the good bet is that those guys have been unlucky.

Except Ryan Howard. Because Ryan Howard. .