Volquez, 26, says he failed the test during spring training. Major League Baseball confirmed the suspension in a press release and said the suspension will take effect April 21.
In a statement Volquez released on Tueday, he said he received the drug -- which was banned by major league baseball -- as part of a prescription in his native Dominican Republic because he and his wife are trying to start a family. "As a result, I tested positive when I reported to spring training. Although I understand that I must accept responsibility for this mistake and have chosen not to challenge my suspension, I want to assure everyone that this was an isolated incident involving my genuine effort to treat a common medical issue.
"I was not trying in any way to gain an advantage in my baseball career," Volquez continued. "I am embarrassed by this whole situation and apologize to my family, friends, fans, teammates, and the entire Reds organization for being a distraction and for causing them any difficulty."
Volquez, who is currently on the disabled list, can serve the suspension while on the DL, but will lose 50 games' worthy of salary.
Volquez was an NL All-Star in 2008, his first year with Cincinnati, and was off to a 4-2 start with a 4.35 ERA for the Reds in 2009 before being shut down with elbow problems. He didn't pitch after June 1 and underwent Tommy John surgery last August. He is still rehabbing and has not pitched yet this season.