Sir Alex Ferguson is crossing his fingers that the virus that has swept the United camp since their return from Turkey last week does not wreck their bid for a derby-day win.
After losing several key players for the weekend win over Wolves, Ferguson had to send more home from training yesterday and admits he has no idea what the make up of his side to face Roberto Mancini's men at Eastlands will be.
In addition, Ryan Giggs and Owen Hargreaves (both hamstring) are definitely out, while Nani (groin) is rated extremely doubtful to recover from the injury he suffered in Turkey last week.
City boss Roberto Mancini could be short of attacking options as Emmanuel Adebayor is doubtful and Mario Balotelli is suspended.
Adebayor has a calf injury and his fitness will be monitored in the hours leading up the to the game while Balotelli is banned after his red card at West Brom on Sunday.
Aleksandar Kolarov is pushing for a place in the starting line-up following his recovery from an ankle injury.
City (from): Hart, Richards, Zabaleta, Bridge, Lescott, Boyata, De Jong, Vieira, Barry, Johnson, K Toure, Y Toure, Tevez, Silva, Adebayor, Kolarov, Given, Milner, Kompany, Boateng.
United (from): Van der Sar, Kuszczak, Rafael, Brown, O'Shea, Ferdinand, Vidic, Smalling, Evans, Evra, Fabio, Obertan, Bebe, Carrick, Gibson, Scholes, Fletcher, Anderson, Nani, Park, Berbatov, Hernandez, Macheda.