RIKERS ISLAND, Queens — It's one of the very largest jails in the country, but as of Thursday morning, a plan to shut down Rikers Island was officially released by Mayor Bill De Blasio.

It was a decidedly soft release, with little fanfare and with the mayor not talking about it publicly, except to respond on a radio call-in show to the concerns of someone affected by the new plan personally. That, as well as some of the terms under which de Blasio's plan would work, provoked criticism from progressives and conservatives alike.

"They ignore all this other work that has been done," said Gabriel Sayegh, co-executive director of the Katal Center for Health, Equity and Justice. "[It] is a baffling decision to make."

Sayegh, whose organization is part of a coalition advocating for the shutdown of Rikers, was comparing the content of the de Blasio administration's 51-page proposal with one published three months ago by a large private panel of incarceration and legal experts led by former New York State Chief Judge Jonathan Lippman.

It is three times the length of de Blasio's newly released plan and goes into greater detail about Rikers's problems, and possible solutions, including replacing the facility with a jail in each of the five boroughs.

De Blasio's new proposal does consider building new jails closer to courthouses in the city's boroughs, but it stops short of building one in each borough, much to the frustration of Sayegh.

"We have thousands of people on [Rikers] Island who don't need to be there," Sayegh said.

Again, somebody who said very little in person and in public about his own proposal was Mayor de Blasio himself.

"I think that's interesting," said Seth Barron, the editor of City Journal, the quarterly publication of conservative think tank The Manhattan Institute. "I think the mayor didn't want to answer a lot of questions about it."

Barron said that could be because the mayor's plan would inevitably be compared to the Lippman report.

Both it and the mayor's plan said that Rikers can be closed if the following objectives are met:

Reducing the prison population from its current level of 9,400 to 5,000

Lowering the overall crime rate in the city, which is already at its lowest ever

Reducing time defendants have to wait for trial

Making bail payments easier to fulfill

Keeping more arrestees, including those for violent crimes, out of jail.

The mayor held no press conference, or any public forum, regarding his plan.

However, during a general interest call-in show with Mayor de Blasio on WNYC public radio, a caller named Anna told the mayor that she had a personal interest in Rikers shutting down.

"My son was sitting for six years on Rikers Island waiting for trial," she said by phone.

"And where is he now, Anna? Where is he now?" asked the mayor.

"Now he is in Mid-State Correctional facility upstate," Anna replied. "He took a plea deal"

When asked by the host what should happen to Rikers, Anna answered, "I believe that people should stay in borough jails next to the courts."

The mayor said that his plan supports that change. However, the way in which it does that, as well as De Blasio's lack of promotion of it, drew criticism from two different fronts.

"He's certainly not showing us vision," said Sayegh. "This is upsetting."

He urged the mayor to more thoroughly incorporate Lippman Report recommendations into his proposals going forward.

Barron is convinced that the need to reduce crime in the mayor's plan will simply reduce penalties for crimes, rather than actually reduce them. Specifically, Barron was critical that quality of life crimes will have little or no consequences in an effort to keep the numbers of arrestees citywide down.

"If those [changes] are put forward," said Barron, "I think that quality of life could go down."