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Using Pitch F/X Data to Determine if Mariano Rivera Threw a Spitball

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As some you may have seen (here and here) there is video from last nights ALCS game of what looks like Mariano Rivera spitting on a ball.  I am not going to judge what he was trying to do, instead I will look at the physical aspects of the "spitball" and compare it to the other pitches he threw last night.  The main advantage of spitting on a ball is to change the spin and direction of the ball.  If there was spit on the ball last night, the ball would act significantly different than other pitches Mariano threw.  I went to the ever reliable BrooksBaseball.net and saw that the spitball pitch was labeled as a cutter.  Imagine that, Mariano Rivera throwing a cutter.  There were nine other pitches last night labeled as cutters.  Here is the spin and break information on those nine pitches:

pitch_type break_angle break_length spin_dir spin_rate spin angle
FC -9.3 5.3 166 1135 166
FC -10.6 5.5 159 1053 159
FC -16.2 5.5 148 1284 148
FC -17.7 5.1 154 1411 154
FC -19.0 5.0 152 1556 152
FC -19.1 4.2 160 1851 160






FC-spitter -19.9 4.4 156 1698 156






FC -24.3 4.8 153 1760 153
FC -26.7 4.1 153 2070 153
FC -26.9 4.0 160 2096 160

The suspect pitch was not unusual from the cutters he threw.  Even if he was trying to spit on the ball for effect, he got no change in break or spin.  People can continue to argue his intent, but for actual effects of the "Spitball" there was no actual advantage gained. 

The actual mental aspect gained might be huge as players will be looking for him spitting now.  It is not like they need something else to worry about when facing Rivera.