Browner, who was named to last year's Pro Bowl after registering six interceptions and 54 tackles in 2011, was hit with a four-game suspension for violating the league's policy on performance-enhancing substances.
The 28-year-old former CFL standout tested positive last month for the prohibited stimulant Adderall, NFL.com reported.
The suspension comes at a key time for the Seahawks, who at 7-5 are battling for an NFC post-season berth. They currently hold the conference's second wild card spot and trail NFC West leader San Francisco by 1 1/2 games.
Browner has intercepted three passes, recorded 44 tackles and forced three fumbles in the present campaign.