Some people love football so much they would play in the NFL for free. San Francisco 49ers linebacker Aldon Smith is going one step further.

Smith, who is eligible to return to the 49ers this week after serving a nine-game suspension, will become one of the rare, if not the only player in league history, to pay for the privilege of playing football, according to sources.

After Smith's nine-game suspension, his salary this season will be $1.099 million, with the net after taxes being $525,000. The 49ers will take all of that from his game checks this season for money he owes due to signing bonus forfeiture, according to sources.

But what he makes this season won't be enough to cover what he owes the 49ers, so the team will take another $661,000 after this season, the sources said.

As @AdamSchefter reported, 49ers Aldon Smith might be the first NFL player to ever PAY to play. pic.twitter.com/zKkalOxjCH — NFL on ESPN (@ESPNNFL) November 9, 2014

Smith's suspension wasn't reduced to allow him to play Sunday, as many expected because while the linebacker did more than mandated in terms of community service, he did not fulfill the obligations assigned him in terms of his counseling protocol, two league sources told ESPN NFL Insider Ed Werder.