ProBasketballTalk reports that the drug in question was marijuana.
The suspension will begin with Denver's first game of the regular season, which is Oct. 29 against the Pistons.
Hickson tore his ACL last March and missed the remainder of the season. A former first round draft pick by the Cavaliers in 2008, the 26-year-old tore averaged 11.8 points and 9.2 rebounds for the Nuggets last season before the injury.
- Molly Geary