Updated

Major League Baseball and the Major League Baseball Players Association announced Thursday they will start random, unannounced in-season human growth hormone blood testing.

The new policy will start in the 2013 season and will expand on the league's current policy regarding HGH.

The MLB and MLBPA's previous joint drug prevention and treatment program allowed for each player to be subject to an unannounced blood test during spring training and an unannounced, random test in the offseason.

Major League Baseball has been randomly testing its minor league players for HGH since July 2010 and is now the only major North American sport to blood test unionized players.

"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."

Records will also be kept on T/E (testosterone to epitestosterone) ratios in players to prevent the unauthorized use of synthetic testosterone.

The league will use the World Anti-Doping Agency-accredited Montreal Laboratory to record a player's baseline T/E ratio, which will be confidentially maintained for comparisons.

"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."

Every player will be tested at least once during the season and the punishments for a player to be found using HGH or testosterone will be the same for steroids, which is a 50-game suspension for the first offense, a 100- game suspension for the second offense and a lifetime ban for the third positive test.