The current diagnosis of his condition is that he has a partial tear to his anterior cruciate ligament. The full extent of the damage cannot currently be assessed due to heavy bruising surrounding the area however Ryan will be re-assessed in four weeks time by which time the injury should be more settled and a full assessment will be possible.
At this stage it is too early to judge how long Ryan will be out however if after a month he is not in pain then the aim would be for him to be fully fit within a further fortnight. If surgery is required, then Ryan would be unlikely to feature for a considerable period.