The midfielder is expected to be sidelined for two to three weeks after suffering a hamstring injury during last weekend's 4-0 defeat to Southampton.
"We have got a real injury crisis at the moment," Pardew told reporters. "We lost Moussa this week in the Southampton game, so of the team that started when we beat Manchester United, five won't play through injury.
"Moussa has a hamstring strain, and we think that's at least two to three weeks."
The Magpies will face United at St James' Park on Saturday.