United's open Premiership game with Tottenham Hotspur on August 18 could be quickly followed by an away game in the Europa League.
The Magpies will have less than two days to get ready for the trip to Stamford Bridge on August 25.
The Chelsea game can’t be moved due to the Met Police’s decision to refuse a request from United.
The whole situation will be eased if the Magpies play their home leg first and the game is switched to the Tuesday night.
Alan Pardew: “The first week could not be worse for us really.
“The activities in London and the Notting Hill Carnival means the game can’t be moved.
“There’s nothing we can do about that.
“It’s our first European game and then two days later at Stamford Bridge for a tough game.
"I can’t see me playing the same team in both games. Physically it is almost impossible.
“I might even leave five players behind and not make them travel because I’m hoping the squad is going to be good enough for two competitions.”PRE-SEASON FIXTURES:
FENERBAHCE 1 NEWCASTLE 1 (Abeid)Elliot, Simpson (Santon 68), Tavernier, Coloccini, R Taylor, Tiote (Bigirimana 59), Gosling (Abeid 73), Obertan (Shola Ameobi 75), Marveuax (Gutierrez 59), Vuckic (Sammy Ameobi 46), Ba (Cisse 68).
MONACO 0 NEWCASTLE 1 (Ba)Harper, Santon (Ryan Taylor 57), Simpson, Williamson (Perch 46), Gutierrez, Amalfitano (Obertan 62), Abeid (Tavernier 46), Bigirimana (Tiote 62), Sammy Ameobi (Vuckic 46), Shola Ameobi (Gosling 62), Ba (Marveaux 78)
CHEMNITZER 1 NEWCASTLE 0Elliot; Tavernier (Simpson, 70), Williamson, Perch, R Taylor (Santon, 70); Obertan (Gutierrez, 77), Abeid (Bigirimana, 70), Gosling, Amalfitano; Vuckic (Shola Ameobi, 70), Sammy Ameobi (Ba, 77). Sub not used: Harper. Att: 6,700
Fri 27.07.2012 NUFC v Olympiakos (at Algarve Stadium, Portugal - 8.45pm KO)
Sat 28.07.2012 NUFC v SC Braga (at Algarve Stadium, Portugal - 8.45pm KO)
Sat 04.08.2012 ADO Den Haag v NUFC (*an exhibition game) (5.00pm KO)
Sat 11.08.2012 Cardiff City v NUFC (at Cardiff City Stadium, Wales - 3pm KO)