To be an expert in the sports world you will first need to narrow your studying to a smaller focus. Starting with a sport or a specific team will help you become an expert at something before branching out.
Here is a list of the most used sports news platforms: http://www.ebizmba.com/articles/sports-websites
To highlight a few:
3) Bleacher Report
To truly become an expert in the sports world you will need to find a passion area and get very specific about it, so that you can be become one of a few people who have the most knowledge about that specific subject. For example, I have a friend who has been referenced on ESPN because he studies the Cleveland Indians solely and has became an expert on them.
Best of luck!