Ronaldo might be benched against Celtic as Carlos Tevez and Anderson are back in contention after missing Saturday's 4-0 win over West Bromwich Albion.
Paul Scholes, Owen Hargreaves and Michael Carrick miss out of course and they are joined in the stands by Patrice Evra who was taken off with a hamstring injury against West Brom and won't be risked tomorrow night.
Michael Carrick and Owen Hargreaves seem set for a return to first team football for Manchester United against West Brom next week when the domestic season restarts after the international break.
Speaking to the Manchester Evening News, Manchester United manager Sir Alex Ferguson said:
“We are expecting Michael to be available next week. He is almost back to full training now.
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Owen Hargreaves is unlikely to travel with Manchester United for their Champions League game against Aalborg on Tuesday.
The England midfielder missed the 2-0 Premier League win over Bolton yesterday because of an ongoing problem with his knee and will not be risked in Denmark.
"Hargreaves is feeling his knee again," revealed manager Sir Alex Ferguson.
Sir Alex Ferguson has backed his Manchester United side to bounce back from their Premier League defeat at Liverpool.
England's preparations for the start of their World Cup qualifying campaign were descending into chaos last night when it emerged that Rio Ferdinand could miss the games against Andorra and Croatia.
The Manchester United defender has been struggling with a back injury that is sure to rule him out of this evening's game here.
Manchester United have named their former midfielder Mike Phelan as assistant manager, while Rene Meulensteen becomes first team coach.
Phelan, 45, replaces Carlos Queiroz, who left his position to take over as Portugal's coach in July.
Dutchman Meulensteen is promoted from technical skills development officer.
Manchester United failed to become the ninth British winners of the Uefa Super Cup when they lost narrowly 2-1 to an impressive Zenit St Petersburg in Monaco.
For the first 60 minutes Zenit were comfortably two goals ahead through a fist half header from Pogrebnyak then a wonderful solo effort from Portuguese star Danny on 58 minutes.
Sir Alex has taken a 19-man squad to Monaco for Friday night’s Super Cup clash with Zenit St Petersburg.
The Reds left Manchester Airport on Thursday morning at 09:00 BST and will train at Stade de Louis II later in the day. Kick-off on Friday night is at 19:45 BST.
Manchester United's Owen Hargreaves has been ruled out of England's opening World Cup qualifiers, adding to Fabio Capello's problems in midfield. Hargreaves, who joins Steven Gerrard on the sidelines, is recovering from tendinitis in his knee and will play in United's Super Cup game on Friday.