I can't tell you the scheme because I can't remember.
That said Matt wants one person to be towards the center of the court (width wise) to play D in transition. We know the rebounds Braden gets and the penetration he gets suggest it isn't him most the time. I don't think it is a particular person as that would hinder that players ability to drive the ball...and from my own personal perspective it wouldn't be the perimeter shooter since I want total focus on the shot...so I think it varies depending on "where" one is when taking the shot. I expect the 2 to be that most the time, but Braden could be that when the 2 is shooting or driving...unless Braden kicked it out to the 2 who ends up shooting and then the 3 man may be that person to head to the center of the court and get in position. I tried to search on centering the ball and think I have a blurb on it somewhere, but I have a lot of things...somewhere.