By choosing to use the exclusive designation, Seymour is prohibited from even negotiating with other teams when free agency starts next month.
With the tag, Seymour will be guaranteed a salary for next season of at least $12.398 million, which is the average salary earned last year by the five highest-paid defensive ends in the league. If the average for next season is greater than that on April 15, Seymour will get the new amount. Oakland would like to sign him to a long-term deal.
The decision by the Raiders not to let Seymour become an unrestricted free agent comes as no surprise after they dealt a 2011 first-round pick to the New England Patriots to acquire Seymour before last season. The only question was whether they would be able to sign him to a long-term deal or would have to use the franchise tag.
Oakland hadn't used the designation since 2008, when cornerback Nnamdi Asomugha was the exclusive franchise player. The Raiders signed long-term deals with Asomugha and punter Shane Lechler before last year's deadline and with kicker Sebastian Janikowski earlier this month.
Seymour, 30, was paid about $3.7 million last season. He was a stalwart in New England after being drafted sixth overall in 2001. He played on three Super Bowl winners with the Patriots, recording 39 career sacks and being selected to the Pro Bowl for five straight seasons beginning in 2002.
Seymour made an impressive debut just days after arriving in Oakland, recording two sacks in a season-opening loss to the San Diego Chargers. But Seymour had only two more sacks in the final 15 games and was unable to solve the Raiders' run defense woes.
The Raiders finished the season 5-11, their NFL-worst seventh straight season with at least 11 losses. Oakland finished 29th in run defense at 155.5 yards per game.