After flip-flopping on bringing Mullan to Seattle, now Smith is blaming Casey's injury squarely on the grass. While I don't think the injury would have happened if they were playing on FieldTurf, I don't think you can say it is primarily the fault of the grass. Injuries like that happen, and all the other guys who played that day avoided injury. The grass is certainly not great (I saw a lot of Man U players slipping on the field yesterday), but Casey's injury could have happened on any other surface.