Hill can participate in all preseason practices and games. His suspension begins Sept. 4, and he'll be eligible to return Sept. 13.
The suspension stems from Hill's January 2009 arrest in Georgia for misdemeanor marijuana possession. He received 12 months' probation through a plea agreement that was settled earlier this spring.
Hill is still facing possible prosecution for his arrest in the Seattle suburb of Issaquah in April for investigation of domestic violence. Hill has pleaded not guilty and is scheduled for a July 23 jury call in the case, with the prosecutor likely to ask for a trial date.
Hill met with NFL Commissioner Roger Goodell last month to discuss his transgressions.
"It was informative, it was a good meeting. Everything went well," Hill said last month of the meeting with Goodell. "It was just a Q-and-A, basically. It was informative. I listened a lot, learned a lot."
Since being drafted by the Seahawks in 2005, Hill has started 61 of 67 games. His best year came in 2006, when he had 92 tackles. Last season, he was limited to just 11 games and 46 tackles because of a torn groin.
Hill signed a six-year, $36 million contract extension with the Seahawks before the start of the 2009 season.
The Associated Press contributed to this report.