The Bills placed Shell on the reserve/retired list Tuesday, Katherine Fitzgerald of The Buffalo News reports.
Shell is not at practice Tuesday and intends to retire, Alaina Getzenberg of ESPN.com reports.
Shell (knee) is expected to be healthy for the start of training camp, Mark Gaughan of The Buffalo News reports.
Shell is expected to sign with the Bills, Jeremy Fowler of ESPN.com reports.
Shell (knee) is inactive Sunday against the Bills.
Shell (knee) is questionable for Sunday's wild-card matchup against Buffalo, Adam H. Beasley of ProFootballNetwork.com reports.
Shell is questionable to return to Sunday's game against the Jets with ankle and knee injuries.
Shell (shoulder) was placed on injured reserve Saturday, Nathan Rauschenberg of the Seahawks' official site reports.
Shell (shoulder) will not play Sunday against the Cardinals, John Boyle of the Seahawks' official site reports.
Shell (shoulder) will not play Sunday against the Lions.