Moussa Sissoko has become the latest player to be ruled out of the game with David Moyes' side as he has suffered a hamstring strain.
The Frenchman has returned to his homeland to receive treatment, and is expected to be ruled out for the next three weeks.
Tim Krul, Mathieu Debuchy and Loic Remy are also unavailable on Saturday, and Pardew admits his side's task is all the more difficult because of the length of the club's injury list.
“We've got a real injury crisis at the moment,” said the Newcastle boss. “We've lost Moussa this week, so of the team that started when we beat Man United, five won't play, although one has left the club.
“Moussa has a hamstring strain and we think it will be two or three weeks. He's been a terrific player for us, and has had a great season.
“He was finding his feet a little bit last season, but this year has served him well. Will Remy be ready for the weekend game? No. We think he's got a chance for Stoke, but we thought he had a chance for this week and are a little bit disappointed that he hasn't.”
Newcastle produced one of their worst displays of the season as they were hammered 4-0 at Southampton last weekend.
The defeat saw the club slip to ninth position, and Pardew is urging his players to produce a positive response to their St Mary's no-show.
“We're all very aware of the performance at Southampton not being good enough for this club,” he said. “We will be doing our best to put in a performance that is worthy. We're disappointed that happened (last weekend) and have to try to put it right.”
Manchester United have been a disappointment for the vast majority of the campaign, but the reigning Premier League champions finally showed glimpses of a renaissance as they claimed a 1-1 draw with Bayern Munich in the first leg of their Champions League quarter-final on Tuesday.
“It's difficult because Man United have had a little upsurge,” said Pardew. “They were terrific against Munich and will bring that bounce to our place.
“We're coming off a very poor performance. Everything points to them being favourites to win this game, but we have to prove that wrong.”