While the Giants are already busy taking a chainsaw to their roster, the Jets and new GM John Idzik have been conspicuously quiet.

That silence doesn’t figure to last much longer.

Gang Green is nearly $20 million over the NFL’s projected $121.1 million salary cap for 2013, meaning Idzik has plenty to do and relatively not much time to do it before free agency kicks off March 12 with the start of the official league calendar.

Actually, getting under the cap will be bloody but simple for Idzik, a cap expert who merely needs to cut outside linebacker Calvin Pace, inside linebacker Bart Scott, offensive tackle Jason Smith and safety Eric Smith to save a whopping $30.8 million in cap room.

But while that might create a healthy bit of space under the cap, it likely won’t be enough for them to give cornerback Darrelle Revis the big-money deal he’s seeking or safety LaRon Landry, who was a key contributor to a defense whose productiveness last year was overshadowed by the woes on offense and a 6-10 finish.

And all those cuts also will leave Idzik and coach Rex Ryan with a vastly depleted lineup, featuring just 10 starters still under contract — including a quarterback in Mark Sanchez who is set to receive $8.25 million will be challenged to retain his starting job.

While David Harris, Santonio Holmes, D’Brickawshaw Ferguson and Antonio Cromartie make big money, cutting them would not help because of the salary-cap hit the Jets would take. It is possible they could restructure their deals.

Then there is the matter of Tim Tebow, who is certain to depart but whose immediate future is still cloudy. That’s because the Jets reportedly plan to see if they can trade him instead of cut him, even though the only team thought to have any interest dealing for Tebow — the Jaguars — recently ruled themselves out of acquiring him at all.