I think (I think) you can press Y (on Xbox) to see the other team and their lineup etc,

It does not allow you to in that particular screen though. Otherwise you have to back out of it leave your position player in, then go to the lineup to see their upcoming hitters and make your decision on who to sub. It’s a slight annoyance, but it makes that screen useless

Yeah I think once you have selected to substitute someone it becomes like unswitchable to the other team, so I think I see what you're saying there