Major League Baseball will reportedly start random, unannounced in-season human growth hormone blood testing during the 2013 season.

CBSSports.com reports that commissioner Bud Selig will make the announcement at the league's owners meeting in Arizona later Thursday.

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 is the only major North American sport to blood test unionized players.

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

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.