Major League Baseball and the Major League Baseball Players Association said Thursday the policy represents an expansion of the game's current HGH rules.
The added policies also call for records to be kept on testosterone-to-epitestosterone ratios to check against the possible use of synthetic testosterone.
"The players are determined to do all they can to continually improve the sport's joint drug agreement," MLBPA Executive Director Michael Weiner said.
"Players want a program that is tough, scientifically accurate, backed by the latest proven scientific methods and fair. I believe these changes firmly support the players' desires while protecting their legal rights."
MLB has been randomly testing players for HGH since June 2010 but not during the season. The MLB-MLBPA release stated each player will be tested at least once during the season. A first offense would result in a 50-game suspension with a second leading to a 100-game suspension. A third offense would lead to a lifetime ban.
"This agreement addresses critical drug issues and symbolizes Major League Baseball's continued vigilance against synthetic human growth hormone, testosterone and other performance-enhancing substances," MLB Commissioner Bud Selig said.
"I am proud that our system allows us to adapt to the many evolving issues associated with the science and technology of drug testing. We will continue to do everything we can to maintain a leadership stature in anti-doping efforts in the years ahead."
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