Hey mate, first of all thanks xd Why am I thanking you, because I wanted to remove a team myself (I added a team to Sports to see if cortana would pick up on them and give me the schedules, but I never removed the team afterwards). Today I did some digging... Obviously we can't remove teams form the app, so it had to be from the website...
I did this on my PC, not sure if phone browser would work, but don't see any reason as to why it wouldn't :)
Here's what you do:
- Head to Bing.com
- Sign in with your MS account (account which you use on the phone)
- Once on the browser page, click on MSN (6th option at the top) (Takes you to the MSN homepage)
- Open sports (should be 4th or 5th option next to your location and weather info)
- Once on the page.. Click on the arrow pointing right (under your profile pic); keep clicking till you see "My Favorites"
- Open that and add/remove any team you like from there