MongoDB store weekly data?

I am trying to think of the best way to store my applications data in weekly chunks.

The app is a basketball statistics app, after all the games are finished for example in week one I would like to store the tracked data into a week 1 database.

Right now all the data is stored using a REST api and the app has 2 collections, one for players and one for teams.

The client side pulls in the teams collection then pulls in the players collection.

I am just lost on how I would go about separating data by weekly, so that the main client side still pulls in the teams and players but in week two has a fresh copy, but in another area in my app I can still pull old data by week.

I hope this is clear enough, I would greatly appreciate some insight.