The commissioner’s office announced the penalty Tuesday.
The 22-year-old Beckham was hitting .204 in 13 games for Triple-A Durham. The shortstop had been on the disabled list because of a sprained left wrist.
Beckham played in the All-Star Futures Game last July after a slow start in his pro career.
In a statement released by the Rays, Beckham said he’s sorry for his actions and takes “full responsibility” for his “poor judgment.”
Rays Executive Vice President of Baseball Operations Andrew Friedman said Beckham “must rededicate himself.”
According to the team’s website, the suspension came after Beckham “tested positive for marijuana for a second time. Marijuana is considered a drug of abuse and a violation under the minor league drug program.”
Beckham was drafted out of Griffin High School — after leading the Bears to the 2008 state finals — before signing a $6.15 million signing bonus. Beckham, who has been a spring training non-roster invitee with the Rays parent club in 2009, 2010 and 2011, hit .042 in 24 at-bats this spring before being reassigned to AAA Durham.
There have been 37 suspensions this year under the minor league drug program.