Players at all positions

[shark-eat-duck]

In section 6.4 of your paper you mention that you could augment these models to include all of the players on the field if the data was available. Theoretically, how would you account for differences in offensive and defensive personnel from play to play? For example, on one play you could have 2 tight ends and another play you could have none. Would you have to build a separate model for every possible combination of players? Additionally, how would you treat multiple players at the same position on a play?

Thanks for making this package publicly available and reproducible - very helpful reference when reading your paper!