(CNN) -- Veteran infielder Miguel Tejada -- a former American League MVP -- has run afoul of Major League Baseball over the issue of prohibited drugs.
Commissioner Bud Selig's office announced Saturday that the Kansas City Royals player has been suspended 105 games, without pay, for violating the league's drug prevention and treatment program.
Tejada tested positive for an amphetamine, the league said in a press release.
His suspension takes effect immediately.
Tejada told ESPNDeportes.com -- according to that website, which is tied to ESPN -- that the positive test stems from his use of Adderall, which he took for attention deficit hyperactivity disorder, or ADHD. He claimed Major League Baseball had given him permission to use the drug, but that permission expired April 15.
"I admit I committed an error, but I want people to understand one thing: I was not taking any drugs to have an advantage on the field," Tejada said.
A native of the Dominican Republic, Tejada broke into the big league with the Oakland A's. He emerged as one of baseball's most dynamic and productive shortstops and hitters, even taking home the American League MVP honors in 2002.
But as he's bounced around the big leagues since then -- including stops in Baltimore, Houston and San Francisco, before landing with Kansas City before this season -- Tejada also has been dogged by performance-enhancing drug questions.
In 2009, he was charged with making false statements to Congress during testimony four years earlier. Days later, he pleaded guilty to a misdemeanor charge and was sentenced to one year of unsupervised probation.
Saturday's suspension comes in the wake of a large group of suspensions affecting players such as Alex Rodriguez and Ryan Braun tied to performance-enhancing drugs out of Biogenesis, a now shuttered south Florida clinic.
The commissioner's office Saturday gave no indication that Tejada's suspension was related to those cases.
CNN's Elwyn Lopez contributed to this report.