The Seahawks listed Walker as doubtful Wednesday because of his oblique strain, putting rookie Zach Charbonnet in line to again fill the starting role.
Walker has not played or practiced since he was injured on the opening drive of the Seahawks' loss to the Los Angeles Rams in Week 11. Coach Pete Carroll said the hope was Walker could return for the Cowboys game after missing Seattle's loss to the San Francisco 49ers last Thursday night.
Instead, the Seahawks will again turn to Charbonnet, a second-round draft pick who gained 94 yards on 29 carries and added 33 receiving yards on 10 catches over the past two games. The Seahawks' other healthy tailbacks are DeeJay Dallas and rookie seventh-round pick Kenny McIntosh.
Seattle's offense has gone seven straight quarters without a touchdown and has found the end zone just three times in the past four games.
The Seahawks also ruled out right guard Phil Haynes (toe) but should get right tackle Abe Lucas back from the knee injury that has sidelined him since the past 10 games. Lucas was listed as a full participant the last two days and doesn't have a game designation.
The Seahawks list defensive tackle Leonard Williams (ankle), tight end Will Dissly (hip) and wide receiver Dee Eskridge (ribs) as questionable, though Williams and Dissly were full participants on the team's estimated practice report Wednesday.
Wide receiver Dareke Young (abdomen) is doubtful.
On Thursday, the Seahawks activated right tackle Abe Lucas off injured reserve and placed right guard Phil Haynes on IR. They also elevated wide receiver Cody Thompson from the practice squad for Thursday's game.
Haynes was already ruled out with a toe injury. The Seahawks don't believe that will end Haynes' season, hoping he'll return for the regular-season finale after spending the requisite four games on IR.