Palace are two points clear of the Premier League drop zone going into their final 10 games, but Chamakh has been ruled out of Saturday's relegation six-pointer with Sunderland.
The Moroccan striker suffered a hamstring injury in the draw with Swansea City earlier this month.
"Cham won't be available this week but we'll assess him in the middle of next week," said Pulis on Friday.
"It's a hamstring (injury) and it's a pretty bad one, which is a blow for us as a football club because he's done so well.
"He's been a real quality player for us. The position we've asked him to play, I think he's enjoyed.
"He's got some quality, especially in the turnover of play. He's most probably our best player at keeping the ball and setting us off.
"Like I say, we've played through Cham and played some really, really good football when he's played."
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