Jason Roberts is the latest Rovers player to come down with suspected swine flu ahead of the team's trip to Old Trafford.
The striker did not report to training on Friday morning and is almost certain to miss the Premier League encounter (kick-off 5.30pm).
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.
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.
Rovers (from): Robinson, Chimbonda, Salgado, Givet, Nelsen, Diouf, Andrews, Pedersen, Dunn, Brown, Jacobsen, Nzonzi, Emerton, Hoilett, Kalinic, McCarthy, Olsson, Jones, Di Santo.