The Seattle Seahawks will be without running backs Chris Carson and Carlos Hyde for a third straight game when they play the Los Angeles Rams on Sunday.

Seattle downgraded Carson (foot) and Hyde (hamstring) to "out" on Saturday after initially listing them as questionable, announcing that news along with several roster moves. The Seahawks activated cornerback Neiko Thorpe off injured reserve, placed defensive tackle Bryan Mone on IR and elevated two players for Sunday's game: running back Alex Collins and defensive tackle Damon Harrison.

Defensive end Benson Mayowa (ankle) was also downgraded to out.

Collins will join Seattle's short-handed backfield for the second week in a row, and Harrison will make his long-awaited Seahawks debut.

The Seahawks' available running backs against the Rams will be rookie DeeJay Dallas, Travis Homer and Collins, plus fullback Nick Bellore. Dallas has started the past two games, but Homer played more snaps last week, 31 to 20, while Collins played 13 snaps in his first game since 2018. Dallas leads Seattle's running backs over that span with 72 rushing yards and two touchdowns on 25 carries.

The Seahawks will be without their top two cornerbacks Sunday, with Shaquill Griffin (hamstring) and Quinton Dunbar (knee) ruled out. Tre Flowers will fill one starting spot, but it's not clear who will fill the other. Thorpe, Seattle's captain on special teams, is one candidate. Others include Linden Stephens, D.J. Reed and Ryan Neal, who previously started at strong safety while Jamal Adams was out.

The Seahawks are 6-2 despite allowing the most passing yards (2,897) through eight games in NFL history, according to the Elias Sports Bureau data. In fact, no team has ever allowed that many passing yards through nine games.

Harrison has been waiting to make his Seahawks debut since joining their practice squad on Oct. 7. The holdup initially was that the 350-pound Harrison had to work himself back into football shape. He had been undecided over the offseason about playing in 2020 due to concerns about the coronavirus pandemic, which he said were eased once he saw how the league was handling travel protocols and other safety measures.

Seahawks coach Pete Carroll has said for the past few weeks that Harrison is physically ready to play. The obstacle, according to Carroll, has been the absence of an opening in Seattle's defensive tackle rotation, which has consisted of Jarran Reed, Poona Ford and Mone. The ankle injury that landed Mone on IR creates that opening.

"We had a plan when I was coming in," Harrison said Thursday in his first comments to reporters since joining the Seahawks. "I needed to work myself back into football shape. The only way you can get into football shape is actually playing football, so I was at home working out, trying to do as much as I could without exposing myself in too many public situations. But I spoke to the coach, I spoke to the general manager before I got here, and we knew it was going to be a process. That's why I've been OK with it just working from the ground up."

The Seahawks will also be without starting center Ethan Pocic (concussion) against the Rams. Kyle Fuller will make his first career start in Pocic's absence.