Sharpton sent a letter to NFL Commissioner Roger Goodell on Monday. He said Limbaugh has been divisive and "anti-NFL" in some of his comments.
Limbaugh did not immediately respond to a request for comment Monday.
Limbaugh said last week that he is teaming up with St. Louis Blues hockey team owner Dave Checketts in a bid to buy the Rams. He has declined to discuss details of the offer, citing a confidentiality agreement.
In 2003, Limbaugh worked briefly on ESPN's NFL pregame show. He resigned after saying Philadelphia Eagles quarterback Donovan McNabb was overrated because the media wanted to see a black quarterback succeed.