The Seahawks placed Chancellor on the reserve/physically unable to perform list, the team announced Thursday. The transaction effectively ends Chancellor's season, and he will not count against the Seahawks' offseason 90-man roster.
Chancellor joined the Seahawks in 2010 as a fifth-round pick out of Virginia Tech, and he emerged as one of the league's top safeties, garnering Pro Bowl honors four times. He and safety Earl Thomas solidified Seattle's back end of coverage, and both were prominent members of the Seahawks' "Legion of Boom" along with cornerback Richard Sherman.
Meanwhile, the Seahawks made other roster moves Thursday.
McDowell's transaction doesn't surprise, as NFL Network Insider Ian Rapoport reported in April the Seahawks were expected to part ways with their second-round pick of the 2017 draft. McDowell suffered a head injury in a vehicular accident last summer and spent his rookie season on the non-football injury list.
The Seahawks signed tight ends Kayaune Ross and Je'Ron Hamm to replace McDowell and Elliott.