The striker did not report to training this morning and is almost certain to miss the Barclays Premier League encounter at Old Trafford.
One player also thought to have suffered with the virus is David Dunn, but the midfielder looked to be in good health when he came off the bench against Peterborough in the Carling Cup on Tuesday night, and is set to play again.
Dying swan: Roberts is felled by Burnley's Brian Jensen
Another is Chris Samba, who is back in training but unlikely to feature as he is still feeling weak.
Pascal Chimbonda returns having recovered from his calf injury and Vince Grella is back in training after his thigh problem, but is unlikely to appear for the first team until next week.
Team (from): Robinson, Chimbonda, Salgado, Givet, Nelsen, Diouf, Andrews, Pedersen, Dunn, Brown, Jacobsen, Nzonzi, Emerton, Hoilett, Kalinic, McCarthy, Olsson, Jones, Di Santo.
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