This is a genuinely neat thing that bodes well for NBA fans who are hoping to see a little more transparency from Adam Silver's NBA. The league has made public an official memo containing guidelines for how referees should be calling verticality plays.
You can read the whole memo, which is very straightforward and even contains video clips of the kinds of plays the league wants referees to start whistling as fouls, right here. If anyone in the league should be worried about this new point of emphasis, it's Roy Hibbert and the Pacers:
We want to make sure you are aware of the following topic we will be alerting referees to today. We have noticed that defenders have been turning sideways when jumping to defend an oncoming offensive player on drives to the basket. This is illegal and referees are being instructed to call this a blocking foul. While we commonly discuss verticality in the context of secondary defenders inside the restricted area (see restricted area and verticality reminder further below), this change will apply to defenders turning sideways while in the air whether inside or outside the restricted area on drives.
Hibbert doesn't show up in any of the video examples provided by the NBA, but for the guy who basically makes his living off challenging people at the rim under the protection of the verticality rule, any increased scrutiny is bad news. Also bad news? The Pacers have scored more than 90 points in just one of their last seven games, and Hibbert is grumbling about selfish teammates. When it rains, it pours.