The NBA is a copycat's heaven; teams are constantly learning from and copying other teams. After the Celtics won the title in '08, for example, suddenly tough defense became de rigueur around the league and amongst announcers and commentators. That's the way it is, and probably the way it should be.
On January 23, the Celtics played the Orlando Magic and, due to team injuries, Avery Bradley started. Though his stat line was mostly unremarkable, by all accounts Bradley was the star of the game, and the single most significant reason the Celtics blew out Orlando to an extent not seen by either team in their entire histories. He did it with his infectious energy, and tenacious, amazing defensive effort. (Neither team did well offensively: Cs scored below their season norm, and shot an anemic 42% FG%. But Orlando's FG% was 24.6%(!), and they scored the fewest total points of their entire history.)
It all started with Bradley's decision before the game – which he conveyed to his coach and other team members – to pick up and guard his opposing point guard at full court through the entire game. That is exactly what he did, and it worked beyond all expectations.
So here's my question: Why is it so unheard-of in the NBA to start the defense at full court? I don't get it. Doesn't the offense start at full court? Why then is it "normal" for NBA defenders to start their defense somewhere between half-court and quarter-court? Why are PGs given a pass when they bring the ball up? Those seconds matter. Why doesn't every quick-and-agile defender play full-court defense? All (or most of) the time!?
Ok, there are some caveats. The defender MUST be quick and agile, so that the opposing PG can't leave him behind and thus get a 5-on-4 advantage in the half-court. And the entire team must be careful to provide good backup, and to not let opponents pick off the full-court defender without warning. But these caveats are obvious, and apply in all situations. They alone do not explain or excuse the lack of complete defense around the league.
I mean.... Avery Bradley is very quick and athletic, to be sure, but he's certainly not the only one in the NBA with those attributes.
The only reason I can think of to explain the absence of the Bradley Defense around the NBA is, in a word, laziness. It's hard. It takes a lot of energy. But.... so what? The WHOLE GAME takes enormous energy, especially if you want to win. Why does all this energy expenditure stop when it comes to playing complete defense? (But ok, if it's too hard to do in every game, one would think they'd at least turn it on for the important/tough ones.)
So here's a prediction. Teams are paying attention. As this season progresses, we will see, from time to time, more of the Bradley Defense played in key games, around the league. And maybe, just maybe, this kind of D will become the new paradigm.
Imo, the Celtics should play this way in EVERY PLAYOFF GAME this season. Every single one. I can't think of a reason not to.
If anyone disagrees, please enlighten.