The Pro Bowl strong safety has missed nine games due to injury and two more because of a holdout since 2014. The Seahawks have gone 6-4-1 while allowing an average of just over 20 points in those games.
But the neck injury that will sideline Chancellor Monday night -- and likely for the remainder of the season -- comes on the heels of cornerback Richard Sherman's season-ending Achilles injury and puts the Seahawks' secondary in an unfamiliar position. Since 2011, the year Sherman and Chancellor joined free safety Earl Thomas in the starting lineup, Seattle has never been without any more than one of those three at once.
"We haven't been in this territory before, but we're excited to see," defensive coordinator Kris Richard said Friday in reference to missing Chancellor in addition to Sherman. "We trust the guys that we're going to put out there. These guys battle, they prepare, they prepare as if they're going to be starters. And it's the NFL; everyone is always one play away. It behooves you to be prepared."
Here's how Seattle's secondary will look Monday night against the Atlanta Falcons at CenturyLink Field -- and possibly beyond:
Jeremy Lane, left cornerback. It's been an eventful few weeks for Lane, to say the least. The 2012 sixth-round pick began the season as the Seahawks' starter at right cornerback opposite Sherman. He was also their nickelback, which is the role he had filled since 2014 when healthy. But he lost both of those jobs after injuring his groin in Week 4. With Lane relegated to a high-priced backup, the Seahawks included him in their trade to Houston for Duane Brown, but he returned to Seattle when he failed his physical. The awkwardness of the situation aside, the Seahawks have touted their good fortune in having Lane back, especially in light of losing Sherman. Former Seahawks starter Byron Maxwell could be an option at some point now that Seattle brought him back this week. Same for DeShawn Shead, another former starter. He's on the physically unable to perform list and is waiting to begin practicing. Lane, though, will get the first shot at taking over on the left side, which won't be as uninviting to opposing quarterbacks now that Sherman is no longer manning it.
Bradley McDougald, strong safety. Signed in free agency to a one-year deal worth up to $2 million, McDougald began the season mainly playing on special teams and occasionally as a third safety in nickel packages. He filled in at free safety the past two weeks while Thomas was sidelined, and now he'll take over for Chancellor at strong safety. The Seahawks felt like they got a steal when they signed McDougald, a former starter with Tampa Bay. He represented a better backup option than what Seattle had last season when Thomas went down in December with a broken leg. The Seahawks are going to get their money's worth from McDougald in 2017.
Earl Thomas, free safety. His importance to the Seahawks' defense was never more evident than when he missed the end of last season. Thomas, a three-time All-Pro, came back strong from his broken leg and has been back to making impact plays, including a touchdown-saving forced fumble against the Rams and a 78-yard pick-six vs. Houston. He's expected to be back for Monday night's game after missing the past two weeks with a hamstring injury. With Sherman and Chancellor out, Thomas is the last man standing of the three original members of the Legion of Boom that remain.
Shaquill Griffin, right cornerback. The rookie third-round pick began the season as Seattle's third cornerback and became the starter on the right side when Lane was hurt. Sherman and Seattle's coaches have often mentioned Griffin's poise. Among other times, that stood out when he held up against Aaron Rodgers and the Packers in his first NFL game after Lane's first-quarter ejection elevated Griffin into an every-down role. He's mostly avoided getting beaten deep, which is a cardinal sin in Seattle's defense, with a notable exception: Griffin allowed a 38-yard completion in the closing minutes that set up Washington's game-winning touchdown in Week 9.
Justin Coleman, nickelback. Coleman had to step in as the nickelback when Lane was ejected in the opener and then again when Lane got hurt, that time for good. He had a pick-six in that Week 4 game and has been solid since then. The Seahawks acquired him for a seventh-round pick from New England on cut-down weekend. That move has paid off, especially considering Seattle gave up relatively little to get him.