That's just the start of the injury concerns in Seattle's backfield and secondary.
Carson's primary backup, Carlos Hyde, is listed as doubtful, and No. 3 running back Travis Homer is also questionable. All three were injured in Seattle's overtime loss to the Arizona Cardinals last week. Homer (knee bruise) was limited Friday. Carson (foot sprain) and Hyde (hamstring) didn't practice all week.
They'll work out on the field before Sunday's game, according to coach Pete Carroll.
"We're going all the way to game time on all three guys and just see what happens then," Carroll said. "We did not practice them this week and that was just to give them every single day to have a chance to get back."
Rookie fourth-round pick DeeJay Dallas is the Seahawks' only healthy tailback. They also have fullback Nick Bellore on their 53-man roster but no other running backs on their practice squad they could elevate for game-day depth. Carroll and offensive coordinator Brian Schottenheimer have said this week that the Seahawks' backfield situation might force them to get creative Sunday and use other skill players at running back.
The Seahawks (5-1) brought in Alex Collins to begin COVID-19 testing Friday, but he won't be eligible to join their practice squad until next week at the earliest.
Dallas has a total of 41 scrimmage yards on six touches in four games.
"He's had an excellent week," Carroll said. "He's really right in the middle of the plan. He's really jacked about the opportunity to carry the load if that would be what happens in this thing. He had a good week. Later as the week wore on, I was making sure we were taking care of him. I didn't want to overwork him. He wanted to take every snap and we didn't let him do that, but he's ready to play."
Defensive tackle Damon Harrison could make his Seahawks debut Sunday -- a potential boost for a defense that's allowed the most yards through six games in NFL history. Carroll stopped short of declaring that the 31-year-old veteran would play but said he had his best week "without question." Harrison, a first team All-Pro in 2016, hadn't played since last season when he joined Seattle's practice squad on Oct. 7.
"This week really ... would make you think that he's ready to come back and play," Carroll said. "He's getting there. The first couple weeks, that wasn't the case. He was just getting back in shape. He's lost some weight. He looks a lot better moving around. He's on his stuff. He knows what he's doing. He's in it. So I'm really fired up that he's competing to get on the field right now."
The Seahawks could either sign Harrison to their active roster indefinitely -- they have two open spots -- or elevate him for game day.
"This week or next week, he's ready to play," Carroll said. "So he would play whatever the game plan allowed him to, so there would be no play count on him. But he's a situational player and does a great job inside tying things up. Our guys are doing OK in there and battling. We don't have any issues rotationwise right now, but he's really made a big step forward this week."
Adams was limited also Friday as he practiced for the first time since injuring his groin in Week 3. He was set to practice earlier in the week before coming down with a non-COVID illness. Adams was sent home, per NFL guidelines, and returned to the team's facility Thursday afternoon after testing negative.
Carroll called it a "real good sign" that Adams practiced Friday but acknowledged the team's reservations about playing Adams on Sunday after just one practice over the past month.
"It's a big concern," Carroll said. "That's a lot to ask. He's worked out great in his conditioning work and all that. The fact that he had to miss a couple days here really kind of threw a wrench into the works for a smooth comeback, so we'll have to see what happens at game time."
The Seahawks ruled out cornerback Shaquill Griffin (hamstring/concussion) and list nickelback Ugo Amadi as questionable. Adams' backup, Ryan Neal, is also listed as questionable, though Carroll said he "looks pretty good." Tre Flowers will likely start for Griffin. Seattle has Linden Stephens and Damarious Randall as options at nickelback and strong safety, respectively. Carroll said D.J. Reed is ready to be activated off the non-football injury list. The former 49er can play cornerback, nickelback and free safety.