Copeland's suspension will begin at the start of the season. He is on the roster of the Class A Batavia Muckdogs of the New York-Penn League.
A third-round selection by Miami in the 2012 First-Year Player Draft, Copeland, 19, batted .280 with 34 RBIs in 62 games between the Marlins' rookie-level affiliate and Class A Jamestown last season. The Louisiana native tallied seven triples.
Zack Meisel is a reporter for MLB.com. Follow him on Twitter @zackmeisel. This story was not subject to the approval of Major League Baseball or its clubs.