A blind pick in a tournament is where both players tell the character that they are going to play to a third and neutral party. This way a player can't "Counter-pick" to a better character before the match even starts.
For Example, I'm going to use Street Fighter because unlike Injustice it doesn't have a "Hidden Cursor" Feature. Let's Say that it's Xian vs Ryan Hart (Both players who have a wide variety of characters to use) And let's say Xian wants to use Dhalsim but he knows that once Ryan sees him pick Dhalsim he will go and pick Yun which is seen as a terrible match-up for Dhalsim. So Xian can call for a Blind Pick in which Both players will tell a neutral party the character that they want to play and that person has to then pick that character (and that character only) for them. That way Ryan just has to guess which character Xian is going to play instead of seeing it at the select screen.
I really hope this cleared it up a little bit... Haha
