I don’t think Watson can use the defence that it was too close to him.
If your arm is in a “natural position” and you get hit from half a yard away then yeah fair enough.
But a keeper charging out of the area and spreading like that doesn’t matter if you are hit from an inch away. If it hits your arm you are done.
I think it was his speed that helped him and the fact that the ref can’t have been sure. Plus I don’t remember now but I don’t recall the Walsall players really making a fuss about it?
