WASHINGTON -- The current labor deal between the NFL and its players' union contains a provision that allows the league to increase the regular season to 18 games. As the sides try to negotiate a new contract, they are talking again about the possibility of making such a switch.

"An 18-game regular season is not uncharted territory," NFL spokesman Greg Aiello wrote in an e-mail to The Associated Press on Wednesday, referring to the 2006 collective bargaining agreement and noting that the CFL and USFL have played schedules of that length.

"The key," Aiello continued, "is to approach it the right way and work closely with our players and clubs to come up with a year-round football calendar that will be better for everyone, including the fans."

League owners and NFL Commissioner Roger Goodell want to expand the regular season from 16 games to 18, and cut the preseason from four games to two. The NFL presented the NFL Players Association with its first detailed proposal covering that issue at a bargaining session in Washington on Tuesday.

Goodell has pointed out that the old CBA already left room for the league to extend the regular season, but he also says he wants to work on any such switch with the union.

The 2006 contract says the NFL would need to give the NFLPA 90 days notice in writing before increasing from 16 games to as many as 18. That agreement also says the league would have to negotiate "with the NFLPA with regard to additional compensation to be paid to players for additional regular season games," and that "if the parties are unable to agree on additional compensation ... (an) arbitrator will have the full authority to decide the amount of additional compensation to which the players will be entitled."

The union has not said it will go along with an 18-game regular season; various players around the NFL have questioned whether it's a good idea.

"The players do not want that to happen," Pittsburgh Steelers quarterback and union representative Charlie Batch said Wednesday, "because that's extra games that are added on to your bodies."

In a joint statement about their latest bargaining session, the league and union said Tuesday's negotiations "focused on several matters," including a longer regular season, a rookie wage scale and improvements for retired players.

"Both sides look forward to continuing these discussions and reaching a new collective bargaining agreement," the statement said.

The current collective bargaining agreement expires in March, and NFLPA executive director DeMaurice Smith has said he believes owners are preparing for a lockout. Indeed, the home page of the NFLPA's official website features a "Lockout Watch" that counts down the days, hours, minutes and seconds until the CBA expires.

The players currently get 59.6 percent of designated NFL revenues, a number agreed to in the 2006 CBA. The owners say that's too much, arguing that they have huge debts from building stadiums and starting up the NFL Network and other ventures, making it impossible to be profitable.

The NFL generates nearly $8 billion in revenues annually, with about $1 billion going to operating expenses. The owners get about 40 percent of the rest, but they want about $1.3 billion more before the players get their cut, and they'd like two more regular-season games to get more money out of the networks for everyone.

Players have said they won't agree to a new deal that amounts to a pay cut. Smith has been warning players since he took office in early 2009 to put aside money in case of a work stoppage.

The union has started the process of having players vote to decertify the union, a step that eventually would allow players to sue the NFL if the owners decide to impose a lockout.

The NFLPA was decertified in 1989, two years after a failed players' strike. It returned as a union in 1993, when a contract was reached with the league that provided for free agency. That landmark CBA has been renewed or restructured several times since 1993, including in 2006. The owners opted out of that deal two years ago.