Colorado Rockies minor leaguer Mike Jacobs carved his name in drug-testing history Thursday by becoming the first North American professional athlete to be suspended for testing positive for human growth hormone.

Jacobs, who has been playing for the Rockies' Triple-A affiliate in Colorado Springs, was suspended for 50 games, effective immediately. The 30-year-old first baseman has played for the New York Mets, Florida Marlins and Kansas City Royals, but hasn't appeared in the major leagues at all this season.

According to the commissioner's office, Jacobs is the first athlete in any North American professional sport to test positive for HGH.

Terry Newton, a former British international rugby league player, was the first athlete suspended for a positive HGH test last year. He admitted taking the substance and was banned for two years. Newton died in September at age 31, found hanged at his home in a suspected suicide.

In March, German rider Patrik Sinkewitz was suspended after becoming the first cyclist to test positive for human growth hormone.

"We have a program in place and it did what it was supposed to do," baseball Commissioner Bud Selig said, adding he wants to get the rule to apply to major leaguers, too. "We don't duck the issue."

The Rockies released Jacobs Thursday after he was suspended.

"We were very disappointed to learn that Mike Jacobs had been suspended after testing positive for a performance-enhancing substance," the team said in a statement Thursday. "The Colorado Rockies have long been committed to eliminating the use of performance-enhancing substances from the game of baseball. We have fully supported the adoption and implementation of the Major League Baseball and the Major League Baseball Players Association joint drug prevention and treatment program."

Jacobs apologized in a statement, saying he used HGH to try to recover from injuries.

"A few weeks ago, in an attempt to overcome knee and back problems, I made the terrible decision to take HGH," Jacobs said in the statement.

"I immediately stopped a couple of days later after being tested. Taking it was one of the worst decisions I could have ever made, one for which I take full responsibility. I apologize to my family, friends, the Colorado Rockies organization, Major League Baseball and to the fans. Now, as required by the minor league drug program, I will serve a 50-game suspension. After my suspension is completed, I hope to have the opportunity to continue my career in the game that I love so much."

Jacobs was hitting .298 with 23 homers and 97 RBIs in 117 games for Colorado Springs this season.

Other professional athletes -- including then-Atlanta Braves prospect Jordan Schaefer, in 2008 -- have been suspended because of evidence that they used, possessed or obtained HGH. But this is the first positive test since blood testing of minor leaguers began in July 2010.

Testing for HGH is not part of the current major league drug agreement, but sources say it's an issue currently under discussion at the bargaining table during baseball's ongoing labor talks.

Rob Manfred, MLB executive vice president of labor and relations, said baseball has looked carefully at what other sports are doing in the area of drugs.

"All sports have the same problems and the same issues," Manfred said. "We've made a proposal on blood testing for HGH and we'll see how it turns out."

Travis Tygart, the CEO of the U.S. Anti-Doping Agency, praised baseball's hard stance on HGH at the minor league level.

"All those that value clean sport know that HGH testing is a necessary part of an effective anti-doping program; otherwise you give athletes a license to use this potent performance enhancing drug with impunity," Tygart said. "This case demonstrates how MLB has stepped up to the plate and implemented HGH testing in the minor leagues to protect clean athletes and the integrity of competition."

Senior writer Jayson Stark covers Major League Baseball for ESPN.com. Information from The Associated Press was used in this report.