Jacob's six-year major league career, in which he hit 100 home runs in 556 games, included stints with the Mets, Marlins and Royals.
After learning of the suspension, the Rockies released Jacobs, who signed a minor league deal with the team last winter.
"We were very disappointed to learn that Mike Jacobs had been suspended after testing positive for a performance-enhancing substance," the Rockies said in a statement.
Jacobs had been playing for the Colorado Springs Sky Sox of the Pacific Coast League, hitting .298 with 23 homers and 97 runs batted in.
He spent most of last season in the minors, appearing in just seven games for the Mets.