Saying he won't be sticking around much past the 2017 mayoral election, Police Commissioner Bill Bratton has declared his independence from Mayor Bill de Blasio.

What he said was nothing less than extraordinary. Police commissioners don't announce their retirements until they are ready to go. Usually they give 30 days, not 30 months.

Furthermore, Bratton apparently blindsided de Blasio. Mayoral spokeswoman Karen Hinton declined to say whether Bratton had alerted the mayor to his announcement. "We don't talk about private conversations the mayor has," she said.

"I will not be commissioner for six and a half years," Bratton said. "That's the reality. I'd be 70-some-odd, 75 years old by that time."

Two Bratton confidants downplayed the remarks as nothing more than "an honest answer to a question."

"He never intended to stay eight years," said a top police official. "He doesn't intend to work until he drops dead. He has a life outside the NYPD." Said another official: "This had nothing to do with de Blasio. It had to do with him [Bratton] and Rikki," a reference to Bratton's wife, Rikki Klieman.

Still, his surprise declaration reflects a couple of things that fall under the heading: "Lessons I haven't learned since Rudy Giuliani dismissed me in 1996 because I felt I was more important than he was."

The first: Bratton still can't keep his mouth shut about himself. The second: He again believes he is more important than the mayor.

Here he may be right. While de Blasio has made misstep and after misstep with the police, Bratton has thrived. He has become both a buffer and a mediator not just between the mayor and officers but between the mayor and a large swath of the public.

De Blasio handled Bratton's announcement like a pro, segueing into a riff on Pope Francis' ability to have impact into his late 70s.

"[Bratton] should do it as long as he feels it's right for him and his family," the mayor said in a statement.

Cynics at Police Plaza suggest Bratton's stated reason for his departure masks something more serious. No one dares say so out loud but on the 14th floor, where Bratton operates, there are whispers of health issues, although this is belied by his packed daily schedule and vehemently denied by his closest aides.

Still, that's what they're saying.