A day after Arik Armstead moved to calm any concern over a foot injury that forced him to leave the San Francisco 49ers' blowout win over the Philadelphia Eagles, the team are now gathering information on a knee issue for the defensive tackle.

Head coach Kyle Shanahan revealed in his Monday conference call that Armstead has a new injury worry, placing his availability for the Week 14 clash with the Seattle Seahawks into doubt.

"We're still gathering more information," Shanahan said on Armstead. "He came in with that this morning. We'll have more on that probably for you guys on Wednesday.

Armstead had been a doubt for the Eagles game because of his foot issue. However, he was healthy enough to play as a disciplined effort from the 49ers' pass rush helped the Niners contain Philadelphia quarterback Jalen Hurts in San Francisco's stunning 42-19 victory.

The 2015 first-round pick left the game in the fourth quarter and did not return, though Armstead insisted after the game that he would be fine.

If he is out for the Seattle game, then Javon Kinlaw would likely step in as the starter at defensive tackle next Javon Hargrave. Kinlaw had two sacks against the Eagles, his first since his rookie year in 2020. The Niners also saw Kalia Davis mark his debut with a sack and have Kevin Givens as an extremely useful part of their rotation on the interior.

On the other side of the trenches, starting right guard Spencer Burford is dealing with another knee issue having returned from a similar injury against Philadelphia. He is considered day-to-day.

"We'll see how he responds this week," said Shanahan of Burford. "He still has a chance to go [against Seattle]."

One player who will definitely miss out against Seattle is third-string tight end Ross Dwelley, who suffered a high-ankle sprain against the Eagles and will be out multiple weeks.

Rookie cornerback Darrell Luter Jr. has a hamstring injury that will keep him on the sideline for a week, while return man Ray-Ray McCloud is still dealing with a rib injury that prevented him from playing in the win over Philadelphia.

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