That first page of tweets clearly say "Foot injury, not achilles" and people are saying "Yup, achilles" or "torn acl" The guy came back in and played still. Neither of those are you coming back in and playing.
That's what I thought as well until someone posted Rapaport, and Pellissero Twitter reports that he's expected to have Surgery on a "significant foot injury"
#Saints DE Marcus Davenport suffered a significant foot injury in Sunday’s loss to the #49ers, sources tell me and @RapSheet. He’s expected to undergo season-ending surgery. A big loss for that defense.