Giants Minor League second baseman Marco Guzman was suspended for 50 games on Friday after testing positive for anabolic steroids.
The Office of the Commissioner of Baseball said the 18-year-old Guzman was using nandrolone, a performance-enhancing substance in violation of the Minor League Drug Prevention and Treatment Program. The suspension will be effective at the start of the 2014 regular season.
Guzman signed with the Giants prior to the 2012 season and has appeared in 93 career games with San Francisco's Dominican Summer League affiliate. Last year the right-handed infielder batted .254 with a homer, 10 RBIs, four steals and a .368 on-base percentage in 46 games.
Nandrolone is an anabolic steroid that, in the past, has been used in the treatment of osteoporosis in postmenopausal women. It's commonly known as Deca-Durabolin and has been linked to several notable baseball players.
Guzman is the fifth player to be suspended this year by the Commissioner's Office -- his suspension comes a day after MLB banned D.J. Driggers and Yonquelys Martinez, a pair of free agent Minor Leaguers, after both tested positive for banned substances.