The Detroit Lions have struggled to put in a game plan for Sunday's game against the visiting Seattle Seahawks.

That's because coach Dan Campbell and the rest of the Lions' staff are unsure which players will be available at kickoff.

Leading rusher D'Andre Swift and top receiver Amon-Ra St. Brown were among the Lions (1-2) to miss practice time this week, as well as receiver Josh Reynolds (ankle), center Frank Ragnow (foot) and guard Jonah Jackson (finger), tight end T.J. Hockenson (foot), linebacker Chris Board (knee), defensive lineman John Cominsky (wrist), cornerback Bobby Price (shin) and kicker Austin Seibert (groin).

In addition, safety Tracy Walker is out for the season with an Achilles tendon injury.

"Yeah, it's not the easiest thing, but you just kind of play the odds, and who do we think has the best chance of playing?" Campbell said. "And you start to lean that way with your game plan early. Then you're prepared to shift if you need to later. But I think you, for the most part, you go with what your gut tells you with the guys who are going to play. And then, how do we work them into the game plan and give them a chance to have success."

Swift, who leads the Lions with 231 yards rushing on just 27 carries and is also a threat as a receiver out of the backfield, appears doubtful with Campbell saying that he might be out until after the team's Week 6 bye. Swift sprained an ankle in the season opener and then injured a shoulder in Sunday's 28-24 loss to Minnesota.

Jamaal Williams, who has 43 carries for 168 yards and four touchdowns, would likely get most of the touches in Swift's absence.

"It has to be significantly better probably to play (against the Seahawks)," Campbell said of Swift. "I mean, it'd have to be the sky's opened up and the bright light comes out and (he says) 'I'm good to go, and it feels unbelievable and here we go.'"

St. Brown, who has a team-leading 23 catches for 253 yards and three TDs, suffered an ankle injury against the Vikings.

"It'll be by committee and we're confident, very confident," Campbell said. "(We) trust those guys."

The Seahawks (1-2) might be in better physical shape -- they placed third-down back Travis Homer on injured reserve because of a rib injury this week, while cornerback Justin Coleman (calf) and defensive end Shelby Harris (glute) missed practice -- but they've struggled in the post-Russell Wilson era.

That's despite his replacement, Geno Smith, having a higher passer rating (100.8) than Wilson, Tom Brady or Aaron Rodgers this season. Smith has a league-leading 77.5 percent completion percentage, but that hasn't translated to points -- especially in the second half, in which Seattle's offense has 10 points through three games.

"I just know that we are at a crossroads right now. We need to get it together, that's the biggest thing," veteran Seahawks defensive lineman Quinton Jefferson said. "Everybody needs to be accountable and go through the film and fix it. I think that's the biggest thing, being disciplined, do your job, and trust your brothers. You have to trust that your brother is going to do their job.

"Again, we have a lot of football left, so we have to get it together."