NFL players have a new teammate in their labor fight—the AFL-CIO.

One of the nation's largest unions said Monday it had sent all of the league's owners a letter warning that a lockout in one of America's "few thriving" industries could cost thousands of Americans their jobs and cities more than $140 million in revenue.

It also urged owners to release financial statements, something NFL Players Association executive director DeMaurice Smith has sought for more than a year. The AFL-CIO called the owners' refusal to provide financial documents "troubling."

"While we are happy to hear that negotiations with the union are continuing, we are disappointed that in the face of your threatened lockout, financial demands and proposed increase in regular season games you have refused to provide any information about your team's profit (or loss) as justification for your requests from NFLPA members," said the letter, dated last Friday.

The AFL-CIO urged owners to consider the potential ramifications a lockout would have on non-football employees such as stadium workers and hotel and restaurant employees, and offered to assist NFLPA leaders by reaching out to elected officials in NFL cities and Congress to seek public hearings on the league's labor issues. The letter was signed by AFL-CIO president Richard Trumka and executive vice president Arlene Holt Baker.

In reply, the NFL asked the AFL-CIO to ensure that the union commits to serious negotiation.

"We share the interest of the AFL-CIO in achieving a negotiated settlement that is fair to fans, clubs, and players, who have received more than $20 billion in salaries and benefits under the current CBA, and who have experienced steady growth in compensation despite the worst economic downturn in our lifetimes," NFL spokesman Greg Aiello said.

"We pledge to the AFL-CIO the firm commitment of the NFL clubs to reach a fair settlement that is good for everyone, especially fans. Nobody knows better than the AFL-CIO that it takes two parties to reach a labor agreement, and we call on the AFL-CIO to encourage the NFLPA to make the same commitment to collective bargaining that NFL owners have made."

Players at the season-opening game Thursday night and six of Sunday's 12 afternoon games walked to the hash marks before their games and raised their index fingers as a sign of union solidarity. Afterward, some players cited the very language that appeared in the letter sent to the owners.

"It's a show of solidarity saying that, 'Hey, we're in it together with all the workers in the stadium, all the police officers that are working extra in here, all the firefighters, all the medical staff, all the businesses around the stadium,'" Houston offensive lineman Eric Winston said Sunday.

"That's what it's really all about. It's about the $140 million that every city loses if we don't have football next year."

The current collective bargaining agreement expires in March, and Smith has repeatedly said he believes owners are preparing for a lockout. He cites the television deals that will pay owners whether the games are played or not as evidence of the owners' intentions, and union reps also have advised players to save additional money.

NFL commissioner Roger Goodell counters that the money must eventually be paid back if the games are not played, and that everyone wants to get a deal finished that assures long-term labor peace in America's most popular sport.

But the issues cited in the letter run deeper than what most consider the key issues to labor peace—salary caps and percentages of the owners' revenue.

Union leaders are also asking owners to provide more extensive long-term health benefits to ex-players, and contends some owners are attempting to change state laws to limit worker's compensation benefits.

"We know that our fellow union brothers face tremendous risks, extremely short careers and a high likelihood of post-career health concerns," the letter said. "Thus, we were surprised to learn that there is no guaranteed health-care for the injuries they suffer from professional football. We also have learned that they must play at least three years to secure only five years of post-career health care and that the NFL is currently challenging hundreds of worker's compensation cases."

The NFLPA also is considering another way to avoid a lockout—decertifying the union.

Should the union decertify, it could have the right to sue the league under antitrust laws if the players are locked out. It is sending out voting cards now because, logistically, getting enough signatures after the season would be difficult, if not impossible.