Harris was released after 10 seasons with the Jets, who confirmed a report by ESPN NFL Insider Adam Schefter that Decker will be released in the coming days if a trade can't be facilitated.
"We advised Eric that if a trade doesn't happen, we'll move forward without him," Jets general manager Mike Maccagnan said.
Decker, 30, underwent hip and shoulder surgeries last fall, but he is healthy and has been practicing. In fact, both players practiced Tuesday before receiving the news.
By cutting Harris and Decker, the Jets will save $13.75 million in cash payroll and cap space.
Maccagnan insisted the Jets aren't giving up on the season.
"It's going to be a competitive roster," he said. "There will be a lot of opportunities for a lot of players on this roster. We are doing things that we feel that are going to help this organization both short- and long-term."
Because of injuries, Decker was limited to three games last season. In his three seasons with the Jets, he caught 163 passes for 2,183 yards and 19 touchdowns.
The team reached out to retired star Steve Smith on Tuesday, seemingly out of due diligence, to gauge his interest in returning to the field, but Smith told the Jets he was not interested, the NFL Network reported.
Harris, 33, the Jets' longest-tenured player, was blindsided by the move. He practiced Tuesday in his usual spot at starting middle linebacker and later talked with ESPN about his longevity as the only holdover from the Eric Mangini era (2006-08).
Minutes later, he was summoned to coach Todd Bowles' office for the news.
"It was an organizational decision," said Bowles, who didn't seem in favor of the move. "They were talking about a pay reduction, and they didn't come to an agreement -- we didn't come to an agreement, and it eventually led to this.
"It wasn't an easy time. David has been a Jet all his life. He was born and bled green. Obviously, he was a guy very well-liked in the building. ... It's part of the business. It's never an easy thing."
Bowles admitted it "happened at a bad time," adding, "There was a breakdown in talks." The Jets approached Harris only a few days ago about a pay cut.
Jets owner Woody Johnson issued a statement on Harris, saying, "For a decade, David Harris represented the Jets with character and professionalism. He held himself to the highest of standards and always carried himself with a quiet dignity and humility. While these decisions are always difficult and the timing is not ideal, David will always be a Jet, and I appreciate his leadership and passion."
The Jets reacquired linebacker Demario Davis on Thursday in a trade with the Cleveland Browns, but that had no bearing on Harris, Bowles said. Sources said there was a sense in the organization even before the Davis trade that Harris was in jeopardy of losing his job.
Harris' agents, Brian Mackler and Jim Ivler, expressed their displeasure in a statement to Schefter.
"Very disappointing in the timing of this event and the decision," the statement said. "The Jets could have done this prior to free agency, instead of waiting three months, especially for a player who has exhibited nothing but loyalty and class for 10 years."
Harris wants to continue his playing career, sources told Schefter.
The coach seemed puzzled by the decision to wait until early June to cut Harris, considering that waiting this long had no benefit in terms of the salary cap.
"That's a good question," Bowles said. "Talks broke down. I wasn't in the meetings. It happened abruptly, obviously."
Bowles sidestepped questions about whether he supported the decision.
"I'm in favor of what we decided as an organization," he said.
Harris was one of his favorite players. Bowles often referred to him as "the glue" on defense, always effusively praising his quiet leadership.
A second-round pick in 2007, Harris ranks No. 2 in tackles in team history. He called the signals for Bowles' defense and played 87 percent of the defensive snaps last season.
Harris, who was known for his durability, started and played in 137 of the past 138 games. He missed one game last season, snapping a streak of 121 consecutive starts.
Before receiving the bad news, Harris told ESPN that he welcomed the return of Davis, who played with the Jets from 2012 to 2015. Davis was acquired in a trade that sent disgruntled safety Pryor to the Browns.
"It was unexpected," Harris said of the trade, "but it's the NFL. Crazy stuff happens all the time."