Using Contact and Pull Rate to Predict a Batter’s Decline

My fellow RotoGraphs writers and I have been working through our 2016 player evaluations. I was tasked with the declining J.J. Hardy. I noticed that two of his core hitting traits, the ability to make contact and pull the ball, had degraded from 2013 to 2014. While Hardy saw an overall decline in his skills when these two skills declined, I wanted to see it was common among other players. I was able to find that decline in these two areas is a sign of a player on a fast decline.

I seeing pulling the ball and making contact as skills which show that a player has the ball speed and vision to keep hitting the ball. To put Hardy’s decline into perspective, here are his Contact% and Pull% values for the past four seasons to go along with his ISO and wRC+.

J.J. Hardy’s Decline

Season	Pull%	Contact%	ISO	wRC+
2013	44.1%	87.8%	0.170	99
2014	41.4%	81.5%	0.104	90
2015	40.1%	84.2%	0.092	49

Both ISO and wRC+ dropped, but again this is the sample of one person.

To see if all players decline when contact and pull rate drop, I ran a simple study. I took the double the change in Contact% plus the change in Pull% to get an overall change value. Then I grouped the players together by changes of  at least 10 percentage points to the good or bad. Going back to 2002, I looked to see how a combined decline affected the player’s stats and the chances for a future rebound (min 200 PA in season one and two). The normal average decline around age 29 is ~ 4 wRC+ and ~.003 ISO.

Results in Decline in Pull% and Contact%

Overall Value (2*Change in Contact%+Change in Pull%)	Age	wRC+ (Y1 to Y2)	wRC+ (Y2 to Y3)	Total Change in wRC+	ISO (Y1 to Y2)	ISO (Y2 to Y3)	Total Change in ISO
Decline of 15% points or more	29.3	-11.4	-7.1	-18.5	-0.011	-0.014	-0.025
Decline of 10% points or more	29.2	-5.8	-5.1	-10.9	-0.009	-0.011	-0.020
Increase of 10% points for more	29.0	3.0	-8.6	-5.7	0.003	-0.009	-0.007
Increase of 15% points or more	29.0	3.5	-13.3	-9.8	-0.001	-0.007	-0.009

I will start off with the 15% Point increase group which doesn’t follow the pattern of the other three. I am not sure if this number is off because of a small sample size issue or if really cranking up the Pull% is the last gasp of a declining player. Otherwise, my inclinations of a declining player were correct. Once a player starts seeing a decline in Pull% and Contact%, their power and overall production decline more than average and there seems to be no regression/bounce back the next season.

With the above results in mind, here are the 2015 players who saw, at least, a 10% drop in the their overall value.

Players on Steep Decline from Drop in Contact% and Pull%

NAME	Contact% Drop	Pull% Drop	Overall Value Change	2014 wRC+	2015 wRC+	wRC+ change	2014 ISO	2015 ISO	ISO change
Hunter Pence	-5.0%	-13.0%	-22.0%	123.9	127.3	3.3	0.168	0.203	0.035
Seth Smith	-7.0%	-8.0%	-21.0%	132.5	113.4	-19.0	0.174	0.195	0.021
Sean Rodriguez	-2.0%	-17.0%	-21.0%	97.6	78.6	-19.0	0.232	0.116	-0.116
Miguel Montero	-8.0%	-2.0%	-19.0%	90.0	107.0	16.9	0.127	0.161	0.035
Victor Martinez	-5.0%	-9.0%	-18.0%	167.2	77.2	-90.0	0.230	0.120	-0.109
Matt Holliday	-4.0%	-8.0%	-17.0%	132.0	124.3	-7.7	0.169	0.131	-0.038
Brett Gardner	-5.0%	-5.0%	-16.0%	111.2	105.2	-6.0	0.166	0.140	-0.026
Travis Snider	-6.0%	-4.0%	-16.0%	122.1	81.2	-40.8	0.174	0.118	-0.056
Alex Avila	-2.0%	-12.0%	-16.0%	97.4	82.5	-14.9	0.141	0.096	-0.046
Rene Rivera	-4.0%	-7.0%	-15.0%	113.4	33.0	-80.4	0.180	0.097	-0.083
Adam LaRoche	-6.0%	-3.0%	-14.0%	127.0	74.8	-52.2	0.196	0.133	-0.063
Kole Calhoun	-6.0%	-1.0%	-13.0%	124.6	104.7	-19.9	0.178	0.167	-0.012
Edwin Encarnacion	-4.0%	-5.0%	-13.0%	151.2	149.6	-1.7	0.279	0.280	0.001
Caleb Joseph	0.0%	-11.0%	-12.0%	71.0	86.3	15.3	0.146	0.159	0.013
Jonathan Schoop	-3.0%	-6.0%	-12.0%	64.1	111.5	47.4	0.145	0.203	0.058
Brad Miller	-3.0%	-7.0%	-12.0%	87.2	105.0	17.8	0.144	0.144	-0.001
Matt Carpenter	-10.0%	7.0%	-12.0%	117.1	138.9	21.8	0.103	0.233	0.131
Brett Lawrie	-6.0%	1.0%	-12.0%	102.9	94.5	-8.4	0.174	0.148	-0.026
Jean Segura	-2.0%	-9.0%	-12.0%	66.1	62.3	-3.8	0.080	0.079	-0.001
Casey McGehee	-6.0%	-1.0%	-12.0%	102.2	52.4	-49.8	0.070	0.076	0.006
Chris Carter	-1.0%	-9.0%	-11.0%	122.2	101.1	-21.1	0.264	0.228	-0.037
Brock Holt	0.0%	-11.0%	-11.0%	97.6	98.2	0.6	0.100	0.099	-0.001
Ruben Tejada	-3.0%	-6.0%	-11.0%	89.1	95.1	6.0	0.073	0.089	0.016
Alcides Escobar	0.0%	-11.0%	-11.0%	94.3	66.6	-27.7	0.092	0.064	-0.028
Andrew McCutchen	-3.0%	-5.0%	-11.0%	169.0	146.4	-22.6	0.228	0.196	-0.032
Nelson Cruz	-3.0%	-4.0%	-11.0%	136.9	158.0	21.1	0.254	0.264	0.010
Hank Conger	-5.0%	-2.0%	-11.0%	82.1	107.4	25.3	0.104	0.219	0.115
Adam Eaton	-5.0%	0.0%	-10.0%	117.1	118.4	1.3	0.101	0.144	0.043
Eugenio Suarez	-1.0%	-8.0%	-10.0%	86.0	104.8	18.8	0.094	0.167	0.072
Jayson Werth	-5.0%	0.0%	-10.0%	140.9	87.2	-53.7	0.163	0.163	0.000
David Peralta	-1.0%	-8.0%	-10.0%	110.1	138.1	28.0	0.164	0.210	0.046
Ryan Zimmerman	-2.0%	-6.0%	-10.0%	119.9	106.7	-13.3	0.168	0.217	0.049
Omar Infante	-5.0%	0.0%	-10.0%	75.6	43.9	-31.7	0.085	0.098	0.013
Kelly Johnson	-1.0%	-7.0%	-10.0%	86.1	106.6	20.5	0.147	0.171	0.024
Mike Moustakas	1.0%	-11.0%	-10.0%	76.1	123.7	47.6	0.149	0.186	0.037
Khris Davis	-4.0%	-2.0%	-10.0%	106.2	120.6	14.3	0.214	0.258	0.044
Leonys Martin	-5.0%	1.0%	-10.0%	89.0	50.1	-38.9	0.090	0.094	0.004

The two names which stick out in the overall value change are Matt Holliday and Brett Gardner. Both had disappointing 2015 season, but the chances they bounce back in 2016 are not good.

This study is just an initial attempt on the subject and a more in-depth study should be done in the future. In the meantime let know what you think and if there could be any additional information added to the formula.