Kosier continues to have problems with a foot injury that kept him out of eight of the first nine games.
He returned after the bye week and played a full game against Washington, but couldn't make it through a victory over San Francisco.
Coach Wade Phillips says Kosier is going to another doctor and may not play again this season.
Dallas is 3-0 in the games Kosier has started, 4-4 in the games he's missed. Cory Procter will replace him, as he did in the eight games Kosier was out.
Jenkins hurt a hamstring against the 49ers. He wasn't starting, so another reserve will inherit his roles.
Phillips says cornerback Terence Newman, tight end Jason Witten and safety Pat Watkins all played through injuries and should be ready to face the Seahawks.