I would say the red is harsh. I would say the defender is trying to make it as easy as possible for his keeper to have a catch with no challenge and is looking to shield the ball from striker. In trying to get to the ball maybe a small push but I would say that a similar thing happens at about 6.40 where player loses ball, slates shields and lad tries to get to the ball and there is a little push, however no collision. I don't know the laws well enough (despite trying to overturn refs decisions for years) to know whether the severity of the injury can alter a decision. The collision is unpleasant and clearly the keeper needed treatment and I am glad that he seems to be on the road to recovery. I do think that this is the sort of decision that could split opinion between officials let alone supporters.