The Seahawks placed safety Earl Thomas on injured reserve on Tuesday, according to ESPN's Adam Schefter.
Thomas suffered a lower leg fracture last week against the Cardinals and was carted off the field. Head coach Pete Carroll did not give a timetable for Thomas's return, although teams are allowed to return two players from their IR list after at least eight weeks of inactivity.
It's unlikely that Thomas, 29, does return to the Seahawks this season, which potentially means he won't play for them again. Thomas, a three-time All-Pro, held out from joining the club for six weeks hoping to secure a long-term extension. He rejoined the club prior to its regular-season opener, and had recently generated reported trade interest from both the Chiefs and Cowboys.
Thomas was scheduled to make $8.5 million this season, the final year of a four-year, $40 million contract he signed in 2014.
Through four starts this season, Thomas recorded 16 tackles and three interceptions, which was tied for the NFL lead.
Through nine seasons with Seattle, Thomas made six Pro Bowl appearances and helped lead the Seahawks to their first-ever Super Bowl title. Thomas is the final remaining member of the team's vaunted secondary unit, "The Legion of Boom," which also lost Richard Sherman and Kam Chancellor earlier this offseason.