NBA players have agreed to submit to testing for human growth hormone provided a neutral panel validates the available blood test for HGH, an NBA spokesman told The Washington Post on Wednesday night.

If its new collective bargaining agreement is ratified, the NBA could become the third U.S. professional sports league since the summer to agree to begin HGH testing after years of resistance.The NBA’s deal would be the most surprising of the three since the league — unlike the NFL and Major League Baseball — has not been under heavy political pressure to include the testing.

But similar to the NFL, which approved the testing in principle when it reached a new collective bargaining agreement in August, the NBA program will not begin until the contingency is met. Indeed, in a memorandum to players, NBA Players Association Chief Billy Hunter said HGH “testing will only be implemented if a committee of jointly appointed experts determine that the tests would be scientifically reliable.”

Major League Baseball’s players have agreed to submit to HGH testing beginning during spring training and later in the offseason, with random testing. The program, however, includes no in-season testing

Attempts to begin blood testing have stalled in the NFL over the players’ insistence that a study be done on growth hormone levels in larger athletes to ensure their natural levels won’t trigger positives. Anti-doping officials have said there are no indications of variations based on size, and no such study is necessary.

The details of the NBA’s testing program were not immediately clear. NBA spokesman Mike Bass did not provide specifics, but said “the parties agreed to implement blood testing for HGH, subject to the test being validated by a neutral committee of experts.” Hunter’s letter said players would be tested for steroids and performance-enhancing drugs a maximum of two times in the off-season and, in the majority of cases, no more than four times during the entire year and never on game nights. It said a joint committee would “study” the implementation of an HGH testing program.

Travis Tygart, chief executive of the U.S. Anti-Doping Agency, said he hoped the validation step wasn’t a veiled attempt to prevent implementation. 

“After seeing the foolishness of the NFLPA, and the clear political tactics to delay testing, you really hope that’s not what this is about,” Tygart said. “An independent panel of the world’s top scientists have already signed off on this test. It’s a little unfortunate [the NBA] has waited until now [to seek the information]. I will show them the independent sign-off tomorrow. Or tonight.” 

The once-criticized test has gained major public credibility in the last year. Though it produced no positive tests in the first five years of its use, from 2004 to 2009, seven athletes have tested positive since late in 2010, and several have confessed to using the drug.

“You don’t have to be a rocket scientist to know that when there is a positive test, and the athlete admits to using HGH, the test works,” Tygart said.