Hali is eligible to return to the Chiefs' active roster on Sept. 10 following their Sept. 9 game against the Atlanta Falcons.
"Tamba's situation is unfortunate," Kansas City Chiefs general manager Scott Pioli said. "Obviously, we are disappointed and will miss him during this suspension, but the NFL's policies are very clear and we respect the league's decision in this matter. We are unable to comment further on this matter or any aspect of the NFL's drug policy."
Due an $11.25 million base salary, Hali will be docked roughly $1.3 million in total pay because of the suspension.
"I apologize to my teammates, the Hunt family, the Kansas City Chiefs organization and most importantly, our fans," Hali said in a statement. "I accept the discipline from the league and will return Week 2 of the NFL season with a commitment to erase this mistake with my play on the field and my conduct off of it."
Hali is eligible to participate in all preseason practices and games.
Hali, 28, had 66 tackles, 12 sacks and four fumbles last season.
He had 14 1/2 sacks two seasons ago.
Over the past three seasons, the 6-foot-3, 275-pounder has 25 sacks.
Hali is a former first-round draft pick from Penn State.
For more coverage of the NFL, go to profootball.scout.com.
Follow me on Twitter: @RavensInsider