NBC Sports requires your have an additional subscription from TV provider (AT&T, Comcast, ...), If you do NOT have TV package, then you only can watch "Highlight" section on NBC Sports Apps, not "Live" or "Replay" section.
There are many different Roku Apps can provide watch "Free" TV & Sports (such as Pluto TV, Redbull,, ...) You need play around to find the ones suite for you.
Other solutions are:
- Adding a HD antenna like Mohu or Clearstream Direct TV to watch Live TV from ABC, CBS, NBC,...
- Adding streaming sports through cheaper subscription $$$ online such as "SlingTV", or "DirecttvNow". These apps are available in Roku.