Was Tyler Chatwood only good this year because he was cheating?
I wasn't sure where to see spin rates for select periods so I pulled up some games in savant.
Chatwood is a bit tricky because he throws mostly fastball variants and not a lot of four seamers. I decided to look only at cutters, since it is a spin reliant pitch.
Date ---- Range CT spin
04-01 ---- 2826 to 2999
04-03 ---- 2690 to 2876
04-05 ---- 2798 to 2995
04-23 ---- 2662 to 2886
04-27 ---- 2517 to 2932
05-23 ---- 2837 to 2981 (struggles begin, two BB and 4 ER)
05-25 ---- 2689 to 2983
05-29 ---- 2549 to 2977
06-04 ---- 2591 to 2787
06-09 ---- 2679 to 2793
06-11 ---- 2557 to 2657 (only threw two)
Results: Inconclusive. Top end and perhaps lower end of CT spin rates appear down in last few games, but the possible decrease in CT spin does not coincide with the beginning of his struggles. Perhaps abandoning the sticky stuff has made a normal blip into something worse?
Limitations: Did not look at average spin in each game, or for each period, because lazy.
Did not look at other pitches. He throws other pitches. But he barely throws the CB and 4S and the SI is typically not a spin-reliant pitch. Throws the CT 38.2% of the time and the SI 47.4%. Someone else could look at the other pitches. Maybe you'd see a decrease in SI spin even if he was just using the sticky stuff for command, or maybe he is weird and tries to spin the SI.
Next Steps: Look at same data in future games.
Someone else might want to look at a bigger sample, his other pitches, and/or his average spin rates per game or per a period.