Scientists, however, appear to be closer to developing a blood test for HGH, which stimulates growth and cell reproduction in humans.

"We all know there is no reliable test for HGH," Gene Upshaw, executive director of the NFL Players Association said yesterday at the union's Super Bowl news conference. "Until a test is developed for HGH, there's really not an awful lot to talk about. And when that test is developed, we really believe it should be a urine test. No one is interested in a blood test. We got a lot of big tough guys, but they don't even like to be pricked on the finger to give blood."

Commissioner Roger Goodell has said repeatedly since taking office just before the 2006 season that the league would implement a test for HGH as soon as one was found.

Upshaw's stance is similar to the one taken by baseball, which has pledged to adopt any validated urine test but does not want to test blood.

Baseball officials have said there is no commercially available validated test for HGH. John Fahey, head of the World Anti-Doping Agency, disputes that, saying two weeks ago that "the storing of blood is practical, in fact has been effectively in practice for some time in World Anti-Doping Code-compliant testing."

Safety Rodney Harrison of the unbeaten New England Patriots, the favorites in Sunday's Super Bowl with the New York Giants, was suspended last Aug. 31 for the first four games of the season after he admitted using "a banned substance" for the purpose of "accelerating the healing process."

Harrison did not acknowledge what the substance was, although he said this week he had made a mistake "and learned from it."

At the time of the suspension, ESPN.com reported that Harrison admitted he obtained HGH.

On the subject of labor, Upshaw said he expects the NFL's owners to opt out of the current agreement later this year. If that happens, the players' union is ready for a strike or the decertification tactics it used to get free agency after the 1987 walkout, although nothing major would happen until 2010, which would be a year without a salary cap.

"If they want to get out of the deal, there's nothing we can do about it," Upshaw said. "But we'll be prepared."

The agreement was reached after tough bargaining in March 2006, and gave both sides the right to opt out in November. That would lead to 2010 being an uncapped year before the contract expires in 2011.

Several owners, including Denver's Pat Bowlen and New England's Robert Kraft, have suggested that the current agreement is leaving some teams cash-strapped, making it likely some owners will opt out next year.

Upshaw said that he's heard the complaints and is ready for any outcome.

"At our meeting in March, our priorities for discussion are four options: strike, lockout, decertification or extension," he said.

Extension has been the route of choice for the NFL since its agreement in 1993 that added free agency and a salary cap for the first time.

The league had been without a contract since its last strike in 1987. After the players returned to work, the union decertified and filed an antitrust suit, which they eventually won. That led to the current CBA, which ended six years without a contract.

In the last 14 years, the contract has been extended numerous times before expiration.

Upshaw said he has discussed the topic with Goodell and would continue past November, if necessary, to try to reach an agreement.

But he warned that the players, who currently get 60 percent of the revenue, will not accept anything lower than that figure. And he said if the two sides get to an uncapped year, there would be no turning back.

"There is not a player in the league who doesn't understand that if we ever get to that point without a cap, we will never have another one again," he said.

Upshaw said the biggest disagreement is among small-market and large-market owners who disagree over non-shared revenue, such as local advertising, concessions and parking. Advertising and local broadcasting rights, in particular, tend to be greater in larger markets or among teams with new stadiums.

In the 2006 agreement, which was the most difficult to reach since the 1993 agreement, the players got an extra $850 million to $900 million in the form of revenue sharing, raising the salary cap for 2007 to $107 million. Upshaw estimated it will be $116 million for 2008.