NEW YORK -- A pair of Dominican Minor League pitchers were suspended Thursday after testing positive for performance-enhancing drugs.

The Office of the Commissioner of Baseball announced that Chicago Cubs right-hander Enyelberth Pena and Padres righty Miguel Severino have been suspended 50 games each following their violations of the Minor League Drug Prevention and Treatment Program.

Pena, with the Cubs' Dominican Summer League affiliate, tested positive for Nandrolone, an anabolic steroid that promotes muscle growth, appetite stimulation, increased red blood cell production and bone density.

Severino, also in the DSL, tested positive for metabolites of Stanozolol, a synthetic anabolic steroid derived from testosterone that has been linked to dozens of professional athletes, including Roger Clemens and Barry Bonds.

Both players will begin serving their suspensions immediately.

Pena had appeared in seven games for the DSL Cubs 2, going 2-1 with a 5.87 ERA in 15 1/3 innings. Severino has not appeared with the Padres at any level in his career.

With the two suspensions, Major League Baseball has now disciplined 36 players under the Minor League program in 2011.