The Office of the Commissioner of Baseball announced that Santana received a 50-game suspension after testing positive for Formestane, a performance-enhancing substance, in violation of the Minor League Drug Prevention and Treatment Program.
The suspension of Santana, who is currently on the roster of Class A Hickory of the South Atlantic League, is effective immediately.
Fromestance is an "estrogen control agent" that reduces excess estrogen in the body by blocking the production of it. Typical results include lean muscle and strength gains, fat loss and increased libido.
Santana signed with Texas as an undrafted free agent, debuting with the organization's Rookie-level affiliates in 2007. He's spent each of the past three seasons at Class A, earning South Atlantic League Player of the Week honored last Aug. 24 with Hickory.
The 21-year-old Loma De Cabrela, Dominican Republic native was batting .260 with 11 homers and 46 RBIs in 75 games with the Crawdads this year.
Santana's suspension comes a day after MLB announced it had disciplined three players, retired journeyman outfielder Jon Weber, free-agent pitcher Guido Gomez and Dodgers' Dominican Summer League pitcher Wilmer Colmenarez. Weber, who retired last weekend, was banned for 100 games after testing positive for a third time.