NEW YORK -- The NFL hopes to start testing players for human growth hormone, and Major League Baseball has started talks with its union to investigate the test that led to the suspension of a British rugby player.

NFL spokesman Greg Aiello said Wednesday that the league had made a proposal to its players in January regarding HGH. Discussions are ongoing, he said.

"Our position is that HGH testing has advanced to the point where we are taking steps to incorporate it into our program," Aiello said. "We have proposed it to the union."

The NFLPA's player development director, Stacy Robinson, said in a statement that the union "has supported research to find a suitable test that will detect sustained HGH use."

"We believe in and collectively bargained for a system that supports the testing of all banned substances," he said.

The NFL has used preseason blood tests since at least 2006 for cholesterol and tryglycerates. In the beginning of January, an NFL management source told ESPN senior NFL analyst Chris Mortensen that the league's position on blood testing -- via a "pin prick to the finger" -- would be pushed only if scientific labs create a successful test for HGH.

Baseball has had urine testing since 2003 but not blood testing.

"We have previously said that if a scientifically validated blood test for HGH is available, we would consider its utilization," new baseball players' association head Michael Weiner said. "But a single uncontested positive does not scientifically validate a test. There remains debate in the testing community about the scientific validity of this test."

The NBA currently uses urine tests for HGH, which is banned on the league's list of prohibited substances.

"We have been and will continue to monitor advances in the testing for HGH for potential inclusion in our program at an appropriate time," league spokesman Tim Frank said.

The issue of HGH testing has gained renewed interest in the wake of the United Kingdom Anti-Doping authority announcing a two-year ban Monday for rugby player Terry Newton, saying he had tested positive and become the first athlete suspended for using HGH.

The substance is believed by some to hasten healing but there is still a debate over whether it increases strength.

A blood test for HGH has been in existence since the 2004 Athens Olympics and available in the U.S. since 2008, according to United States Anti-Doping Agency executive director Travis Tygart.

Tygart said the test was available to professional leagues, but only through World Anti-Doping Agency labs.

"It's one that's been well-vetted, well-discussed," he said by telephone from London. "Further research has been done to get it to a point where it's scientifically valid, and we're happy to help any entity that's interested in having an effective test, whether we're involved with their program or not, getting them comfortable with the validity of the science."

The NFL and NFLPA can change the terms of the collectively bargained steroids-testing program without a new labor contract. But the union is balking.

"At this point, there's no reason to believe that blood-testing for NFL players will or should be implemented," George Atallah, union assistant executive director of external affairs, told The New York Post. "We should instead focus on preserving the drug-testing policy that we have in place."

While MLB can institute blood tests for players on minor league rosters, it must reach an agreement with the players' association to start blood testing for unionized players on 40-man big league rosters.

"We are well aware of the important news with respect to the HGH blood test in England," Major League Baseball said in a statement. "We are consulting with our experts concerning immediate steps for our minor league drug program and next steps for our major league drug program. The commissioner remains committed to the position that we must act aggressively to deal with the issue of HGH."

Tygart said the window for detecting HGH through the test is three days at the most, making it most useful for out-of-competition testing. According to Weiner, it may be even shorter.

"Even those who vouch for the science behind the test acknowledge that it can detect use only for a day or so prior to collection," he said.

Baseball began random urine testing for players on minor league rosters in 2001 and reached an agreement the following year to start testing unionized major leaguers.

"I'd prefer urine testing. It's easier, especially for people who are afraid of needles," said infielder Josh Vitters, the Chicago Cubs' top draft pick in 2007.

Outfielder Brett Jackson, Chicago's No. 1 pick last year, understands why the minor leaguers might get tested first.

"We're guinea pigs for almost everything else," he said, "so why not?"

Information from The Associated Press was used in this report.