MLB to introduce random in-season HGH testing

Major League Baseball Commissioner Bud Selig (left) and Major League Baseball Players Association Executive Director Michael Weiner speak at a news conference at the headquarters of Major League Baseball on November 22, 2011 in New York City. / Photo by Patrick McDermott/Getty Images

Major League Baseball is set to announce unprecedented measures to stop the use of human growth hormone, reports Jon Heyman of CBSSports.com. Commissioner Bud Selig will make the announcement at the owners meetings in Arizona on Thursday.

Starting this season, MLB will conduct random, unannounced, in-season blood testing for HGH. The league will also keep detailed records on T/E (testosterone to epitestosterone) ratios to combat questions about testosterone levels, CBSSports.com reports. All players will be tested at least once.

The announcement of the more stringent testing comes one day after baseball's Hall of Fame denied entry to Barry Bonds, Roger Clemens and Sammy Sosa - star players who have been linked to steroids.

• Bonds, Clemens, Sosa snubbed in Hall of Fame shutout

"The MLB Players Association was averse to any sort of testing whatsoever, but in the past two years -- under the leadership of Michael Weiner, who took over as executive director in December of 2009 -- significant strides have been made in the effort to clean up the game," writes CBSSports.com's Matt Snyder.

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MLB players banned for positive drug tests

Last season, Melky Cabrera and Bartolo Colon were among several notable players who were suspended for positive drug tests. Former National League MVP Ryan Braun also tested positive but his result was overturned on appeal.

The National Football League still does not test for human growth hormone. The NFLPA won't concede the validity of a test that's used by Olympic sports and pro baseball, and the sides haven't been able to agree on a scientist to help resolve that impasse. HGH is a banned substance that is hard to detect and used by athletes for what are believed to be a variety of benefits, whether real or only perceived -- such as increasing speed or improving vision.