ARLINGTON -- Ji-Man Choi, a first baseman for the Mariners' Triple-A Tacoma club, received a 50-game suspension without pay Thursday after testing positive for methandienone, a performance-enhancing substance, in violation of Major League Baseball's Joint Drug Prevention and Treatment Program.
Choi, who is on the Mariners' 40-man roster, was hitting .394 with one home run and five RBIs in 10 games for Tacoma this season.
The suspension is effective immediately.
Choi released a statement of his own saying he didn't knowingly take any illegal substance.
"A banned substance was detected in my urine sample," Choi said. "I do not know what I could have taken that caused me to test positive. I have not and never would knowingly use anything illegal to enhance my performance. However, I also understand that without an explanation I must serve a suspension and I accept that. I look forward to putting this behind me and to returning to help the Mariners ballclub once my suspension has ended."
The Mariners issued the following statement:
"The Seattle Mariners are disappointed to learn of today's suspension of AAA infielder Ji-Man Choi. The organization fully supports Major League Baseball's Joint Drug Prevention and Treatment Program and its efforts to eliminate performance-enhancing substances from our game. Per the Basic Agreement, the Mariners will have no further comment."
Choi is a 22-year-old from South Korea who signed with the Mariners in 2009 and has played four years in their Minor League system, though he sat out all of 2011 with a back injury.
Choi hit .295 with 36 doubles, six triples, 18 home runs and 85 RBIs in 122 games last year while splitting time between Class A High Desert, Double-A Jackson and Tacoma.
Choi will be placed on a restricted list, which opens up a spot on Seattle's 40-man roster.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.