Using Contact and Pull Rate to Predict a Batter’s Decline by Jeff Zimmerman December 21, 2015 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.