This from Sky: Rio Ferdinand is definitely out, and will obviously be missing for some time, allowing Wes Brown to bid to cement a regular place in central defence in his fellow England international's absence.
Transfer-seeking Nicky Butt is, as expected in the squad, with Phil Neville suspended.
United's A-list stars look set to sit out the tie, following a break in Dubai, so Ruud van Nistelrooy, Ryan Giggs, Roy Keane and Paul Scholes should make way for the likes of Diego Forlan, Kleberson, Quinton Fortune and Cristiano Ronaldo.
Northampton have former United player Ashley Westwood due to line up against us
Gaz Nev on the hazards of playing lower league teams:
"Down the years we've come up against the strongest, most physical teams in Europe so we are not exactly pussycats ourselves.
"We play physical games every week and Northampton won't be any different.
"Both teams must make sure they play within the rules and if we don't, I'm sure the referee will step in to sort it out."
"The best way of avoiding complacency is to think about the consequences of defeat," added the 28-year-old Bury-born player.
"This game is a massive opportunity for Northampton. We understand that and we respect it.
"We saw last week it is not always the team you expect to win that actually does so.
"They will be looking for any advantage they can get and if we show nerves, they will try to exploit it.
"The nearest situation I can remember to this one is when we played at Reading a few years back. We got through that game because we were professional and we need to do the same again."