Other than being his mandatory have no idea how close it may be. Really hope Brook doesn't vacate as it's a helluva match up for the sport. And secondly it means Spence would possibly fight Berto and as a result be charged with attempted homicide . Brook would do well to take a step back fight at 147 if that's his route because a Golovkin beat down tends to live on a guy for a while. You do not erase that in the span of a fight. Spence has yet to face a top tier talent but in all honestly I'm beginning to attribute that to him and the sheer tenacious skills he's exhibited more than not looking for them. The way he varies the steam on combinations is simply awesome.