Detailed per play/player stats involve quite a bit of effort to collect, and thus are not typically free. Sports stats in general is a fairly closely guarded and proprietary area. Here an interesting article about it from 2014: https://fivethirtyeight.com/features/the-people-tracking-eve...

I have to assume computer vision will largely automate the process of collecting sports stats, even in real-time, if that hasn't already happened. For that I think you would need access (and licensing rights) to a quality video feed of the matches, different than what is broadcast for human consumption (i.e. shows the entire field of play the whole time).