Pridie, 28, is on the roster of the Oakland Athletics' Class AAA affiliate in Sacramento.
Major League Baseball didn't provide details of the violation other than to say it was for "a drug of abuse."
Pridie was a second-round draft pick by Tampa Bay in 2002. In 2007, he went to Minnesota along with Delmon Young and Brendan Harris in return for Matt Garza, Jason Bartlett and Eduardo Morlan, and made his MLB debut with the Twins in September 2008. But he didn't stick with the club and in February 2010 the Mets claimed him on waivers.
He hit .231 in 101 games last season with four homers and 20 runs batted in. Oakland signed him in the off-season.