As soon as official word came down that James Bradberry was no longer on the Giants’ roster, a message came through on the defensive backs’ text chain. It was created by Adoree’ Jackson, and it sent a clear signal to the remaining cornerbacks, cajoling them not to wilt under the heat of critical scrutiny now that the leader of the group was gone.

Bradberry was released so that the Giants could gain $10.1 million in salary-cap relief. The new front office and coaching staff acknowledged this would be a better team with Bradberry, but the finances just did not fit.

What was left behind? A group of cornerbacks, which outsiders are eager to circle as a reason why the 2022 Giants defense will not make the grade.

“It’s just an opportunity for us as individuals to do what we have to do and step up and go play and do something for ourselves,’’ Jackson said of his message to his teammates. “Because the situation is going to hit us all, whether we want to or not. Go out there and do what you can do and compete and make it hard for them to not want to make those changes.’’

Just like that, Jackson moved up in the pecking order, from CB2 to CB1. That will be a daunting challenge — for Jackson, for new defensive coordinator Wink Martindale, for returning cornerbacks coach Jerome Henderson and for new head coach Brian Daboll. Martindale is demanding that the corners play aggressive man coverage, a departure from the preponderance of zone defenses used by the Giants in 2021.

At the start of his NFL career, linking Jackson to a top-tier cornerback spot was realistic, but he did not live up to that advance billing, and nowadays, he is going to have to get a whole lot done to be seen as a bona fide No. 1 corner.

“It’s me believing in myself and the confidence that I have put in the work,’’ Jackson said. “Confidence comes from mentally and physically being prepared, so no matter what the situation is, no matter what the task is, you go out there and you’re confident in your prep and mentally being prepared for what you’re doing, the sky’s the limit. At the end of the day, it’s on you.’’

Jackson was the 18th-overall pick in the 2017 draft, a hotshot out of USC, and he became an immediate starter for the Titans, with varied success, until a knee injury limited him to just three games in 2020 and he was released. The Giants, with money to spend, wrote a three-year, $39 million contract in free agency, a deal instantly panned as exorbitant by most talent evaluators.

Jackson played in 13 games in his debut with the Giants in 2021, missing time late in the season with a quad injury. Though he is best remembered for dropping what should have been a game-sealing interception in the end zone in a Week 3 loss to the Falcons, he actually was an effective player. Pro Football Focus graded him as the No. 15 cornerback in the NFL, and his coverage rating was fourth-best — behind just Jalen Ramsey, A.J. Terrell and Darius Slay. By comparison, Bradberry was ranked 58th among all cornerbacks, a down year after a Pro Bowl 2020 season with the Giants.

Henderson said he is not looking at any player as “CB1” and has asked Jackson, who is just 26, to mentor the younger players — including Aaron Robinson, Rodarius Williams, Darnay Holmes and rookie Cor’Dale Flott.

“Be that guy that takes them under your wing and talks about your development and how you got here,’’ Henderson said. “Earning a second contract in this league is a big deal, and the second contract he got is a big deal. Help them have that career that they earn that second contract like he did.’’

Jackson grew close to Bradberry in their one season as teammates and admitted it was “devastating’’ to see him leave.

“But at the end of the day, I gained a brother in the process of knowing him,’’ Jackson said. “It’s like your brother going off to college. He’s my brother, he goes somewhere else but at the same time still being in touch with him and happy for him.’’

Jackson is planning on a jersey swap when the Giants play Bradberry’s new team. That will be twice this season, as Bradberry signed with the Eagles, a heated NFC East rival.

“That sucks,’’ Jackson said.

Bradberry’s assignment — running with opponents’ top receivers — now will fall to Jackson.

“Obviously if you’re given a role, you have to believe that you can do it,’’ Jackson said, “and do it at the highest ability.’’