Orlando Magic forward Hedo Turkoglu was suspended without pay for 20 games on Wednesday for violating the terms of the NBA's anti-drug program after testing positive for methenolone.
Turkoglu will begin serving the suspension Wednesday night when the Magic play host to the Atlanta Hawks.
He said he was given medication by a trainer when he returned to his native Turkey this past summer to recover more quickly from a shoulder injury.
"I didn't know that this was a banned substance and didn't check before taking it," Turkoglu said in a statement. ""I take full responsibility for anything that goes into my body.
"This was a complete error in judgment on my part and I apologize to the Orlando Magic organization, the league, my teammates, and the Magic fans. I know I have let down a lot of people and I am truly sorry for my mistake."
Magic general manager Rob Hennigan said Turkoglu unknowingly took a banned substance.
"There are more than 125 banned substances on the NBA list, and we spend a lot of time educating our players on the contents of that list and will certainly continue to do so moving forward," he said. "We believe this was an honest mistake."
Turkoglu, 33, suffered a broken hand in the Magic's season opener on Nov. 2 and underwent surgery. He didn't return until Dec. 29 but struggled with the hand and conditioning and has played in only 11 games this season.