I've wondered about concussion effects too, does anyone know how much, if any, effect it could have on one's depth perception? I haven't watched every game but a few times I've seen Joe not quite get to a foul pop fly by, what looks like, misjudging where its coming down. Could be sun related or any number of things, but depth perception issues could explain the higher number of swing-and-misses we've seen this year. Again, it's all speculation but after the years of taking a beating by the local media and fans for being "soft" maybe he's trying to play through (and hide) something to shed that label cause there's no "catching is tough on the body" playing first base.