Cameron, who spent the past two seasons with the Padres and is eligible for free agency, was found to be in violation of Major League Baseball's Joint Drug Prevention and Treatment Program.
The suspension of the 34-year-old Cameron will be effective at the start of the 2008 season. He believes he tested positive for a tainted supplement.
"The one thing I wanted to make sure was explained is, no steroids," Cameron told AM 1090, the Padres' flagship radio station. "I never took nothing like that before in my life. That would be 50 games, and that would affect me a whole lot more."
In a statement issued through his agent, Mike Nicotera, Cameron indicated that the Major League Players Association helped him narrow down what triggered the positive test.
Players who initially test positive for a stimulant receive counseling and are subject to increased drug testing over a period of time. At the time of the initial drug test, the player should be made aware of the questionable stimulant. A player only faces suspension if he tests positive a second time for a similar stimulant.
"After all of the analysis and testing, I can only conclude that a nutritional supplement I was taking was tainted," he said. "Unfortunately, the actual supplement is gone, and therefore cannot be tested. Without the actual supplement in hand, the rules are clear, and I must accept the suspension," the statement said.
Cameron hit .242 with 21 home runs and 78 RBIs in 151 games for the Padres this past season.
The three-time Gold Glove winner is a career .251 hitter with 216 home runs and 786 RBIs with the Padres, White Sox, Mariners, Reds and Mets.
"Mike has been a valuable member of the Padres over the last two seasons who has been respected for his contributions on the field, his stature in the clubhouse and his involvement in the San Diego community," Padres chief executive officer Sandy Alderson said in a statement.
"Accordingly, the Padres are extremely disappointed that Mike has tested positive for a stimulant banned by MLB's drug policy. Nonetheless, the Padres staunchly support that policy and hope that Mike's suspension serves as a reminder that performance-enhancing drugs have no place in professional sports."
Cameron has yet to file for free agency but was expected to do so this week. In April, the Padres had some discussions with Nicotera about signing Cameron to a contract extension but it was decided that talks would be tabled until after the season.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.