NEW YORK -- Union chief Billy Hunter said Thursday "it's obvious the lockout will happen tonight" after players and owners failed to reach a new collective bargaining agreement, potentially putting the 2011-12 season in jeopardy.

With this latest action, two of four major professional sports in the United States are locked out. The NFL locked out its players in March, and the two sides have been in discussions this week, trying to work toward a new deal.

Despite a three-hour meeting Thursday and a final proposal from the players, the sides could not close the enormous gap that remained in their positions.

"The gap is too great," Hunter said.

The CBA expires at midnight, after which all league business is officially on hold, starting with the free agency period that would have opened Friday.

Commissioner David Stern said "with some sadness" he would recommend later Thursday to the labor relations committee that the first lockout since the 1998-99 season be imposed.

"Needless to say we're disappointed that this is where we find ourselves," deputy commissioner Adam Silver said.

Hunter said he hopes the two sides will meet again in the next two weeks.

"The negotiations ended without a resolution. The NBA informed us they are making a recommendation to their labor relations committee to start a lockout at midnight," union outside counsel Jeffrey Kessler told ESPN's Kelly Naqi. "The players want to continue to play basketball and are very disappointed."

All league business is officially on hold, starting with the free agency period that would have opened Friday, and games eventually could be lost, too. The last lockout reduced the 1998-99 season to just a 50-game schedule, the only time the NBA missed games for a work stoppage.

"We tried to avoid the lockout; unfortunately, we couldn't reach a deal," union executive committee member Matt Bonner said.

The sides remained far apart on just about every major issue, from salaries to the salary cap, revenues to revenue sharing.

Players, who previously offered to reduce their salaries by $500 million over five years, considered the owners' proposal for a "flex" cap, where each team would be targeted to spend $62 million, a hard cap. Although the league said total player compensation would never dip below $2 billion over the life of its proposed 10-year deal, that would amount to a pay cut for the players, who were paid more than $2.1 billion this season in salaries and benefits.

Owners also wanted a reduction in the players' guarantee of 57 percent of basketball revenues.

The players' association seems unlikely, at least for now, to follow the NFLPA's model by decertifying and taking the battle into the court system, instead choosing to continue negotiations. Hunter said last week he felt owners believe the 8th U.S. Circuit Court of Appeals in St. Louis, which is debating the legality of the NFL's lockout, will uphold employers' rights to impose lockouts.

The NBA's summer league in Las Vegas already has been canceled, preseason games in Europe were never scheduled, and players might have to decide if they want to risk playing in this summer's Olympic qualifying tournaments without the NBA's help in securing insurance in case of injury.

Training camps usually open the last week of September and the regular season about a month later. [ Register or Signin to view external links. ]