The transaction was a formality after coach Pete Carroll said Friday he expected the strong safety to start after missing the first two games of the season in a contract holdout.
"He's looked like he's in just rare form," Carroll said, via the Seattle Times. "So he looks like he's going to be able to play some football and we are looking forward to that."
Carroll later acknowledged that "it is not unrealistic" that Chancellor plays all four quarters on Sunday versus the Chicago Bears.
To make room on the roster the Seahawks waived safety Dion Bailey. It was a fast fall for the second-year pro. Bailey started Week 1 in Chancellor's place, but committed a glaring fourth-quarter error in coverage that led to a game-tying touchdown in Seattle's loss to the St. Louis Rams. Thirteen days later, the 23-year-old got cut.
It's another reminder how quick the tides turn in the NFL. Bailey has practice squad eligibility if he passes through waivers.