The Brazilian international is now facing four weeks out of action as a result of the injury picked up in the Blues' 1-0 success against Mark Hughes' men in the fourth round of the FA Cup.
Ramires failed to finish the game at Loftus Road because of the knee problem but manager Andre Villas-Boas isn't expecting him to be missing from action for long.
"It looks like a medial knee ligament injury," Villas-Boas said.
"It is not so bad in terms of the worst knee injuries but he'll have the MRI scan tomorrow and we'll know the full extent and I think hopefully he is going to avoid an operation.
"We have to know the extent of the ligament injury and eventually with the treatment and results we have been having medically, we could be looking at a four-week period.
"We have to look at the extent of the injury. Maybe more than that, but hopefully not."