The shot was deflected on its way toward the net and came up and hit Staal near his right eye. As you can see in the video, Staal does not wear a visor.
Whenever something like this happens, it renews the debate as to whether visors should be mandatory in the NHL. Though a large number of players in the league wear them, they're not required equipment in the NHL.
They are mandatory in the American Hockey League and all Junior leagues. It's because of those rules at the lower levels that so many of the incoming young players are already wearing them (they're used to wearing them and stick with them). But there are still some exceptions. And every once in a while, something like this happens.