Rejected! Celtics head coach told to stop contesting shots

In an appearance on "Zolak and Betrand," Mazzulla revealed that "I've been told I can't do that anymore." Mazzulla did not reveal who it was that delivered the ban, but it sounds irrevocable.

The play in question came when O'Neale, who hadn't made a shot in the game, heaved up an attempt after a timeout was called late. Mazzulla closed out and leapt to prevent the shot himself.

While Mazzulla and his staff see it as a way to bond with their players, you can see how the NBA might not want its coaches playing aggressive defense in dead-ball situations. 

Imagine the uproar if Mazzulla had landed underneath O'Neale and he sprained an ankle, for example.

Mazzulla isn't the only coach who's gotten a little too involved. In January, Memphis head coach Taylor Jenkins ran on the court to protest a non-call, and ended up playing defense on the Lakers' Taurean Prince. 

He got a well-deserved technical foul.

The Celtics players will have to finish the season blocking shots after the whistle all by themselves. Still, Mazzulla seems to have no regrets.

"That was 100% move to break the barrier between coach and player to say, ‘Hey, we are all out here to compete together and we all have a standard we try to hold to," Mazzulla told the hosts. "I appreciate the players allowing us to be ourselves."

They'll just have to be themselves from the sidelines from now on.