On Sleeper, we allow you to block other users from sending you direct messages and from seeing their comments.
Blocking somebody does not remove them from any leagues, but provides a way for you to avoid seeing any of their comments or chats.
You can block another user by selecting their avatar from the league chat. You'll see an option to block them in a pop-up window.
On mobile, you'll need to select the More option and then block:
On the web app, you can tap on block in the bottom right:
To unblock them, you will have to go to the web app. Click on Direct Messages in the top left, and then click on View Blocked all the way to the right.
This will bring up a list of your blocked users, and you can unblock them at any time: