FLORHAM PARK, N.J. — The Jets haven’t played a preseason game yet, but they already have lost their top wide receiver for the season.

Coach Todd Bowles announced after Monday’s practice that Quincy Enunwa has a bulging disc in his neck and will be out six to nine months.

Enunwa is expected to have surgery, pending a second opinion.

Bowles said he was told that Enunwa’s injury isn’t career-threatening.

“Going forward, we’ll see,’’ he said. “They said he should come out of it OK.”

The roster move came two days after Enunwa, 25, reinjured his neck at the team’s Green and White scrimmage Saturday at MetLife Stadium. He suffered the non-contact neck injury while the offense was participating in 7-on-7 practice drills before the scrimmage.

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According to Bowles, Enunwa felt a “tingling feeling” in his neck during the spring and had some tests and received treatment.

“He was doing better, he was doing fine,’’ Bowles said. “When he fell the other night, it just flared up again . . . I don’t think he had [a bulging disc] in the spring. It was treatable in the spring. He was healthy.”

The 2014 sixth-round pick caught 58 passes for 857 yards and four touchdowns in 2016 and figured to be the team’s No. 1 receiver after the departures of Brandon Marshall and Eric Decker.

Now, with the Jets’ preseason opener coming up Saturday against the Titans, the coaching staff must figure out how to generate more offense from an inexperienced receiving corps.

“He’s a big part of it,” Bowles said of Enunwa, “so our young guys are just going to have to grow up fast.”

Bowles was quick to invoke the “next man up” mantra.

“It’s not deflating,” he said of the Enunwa news. “Injuries are a part of the [game]. You take body blows in this league. Guys have to step up and we have to coach them.”

Bowles also insisted that his confidence in his young receivers hasn’t waned.

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“It hasn’t changed,’’ he said. “Obviously, they have to get some experience and get some reps. But they’re talented. Just have to learn and get caught up to speed.”

Fellow wideouts Robby Anderson and draft picks ArDarius Stewart and Chad Hansen were not made available to the media Monday.

The organization waived former 49ers receiver Bruce Ellington on Saturday, just a day after he was claimed off waivers. The Bills added veteran leadership Monday with the signing of receiver Anquan Boldin.

The Jets will look into adding another receiver, but it’s unclear if he will be a veteran or another camp body.

“We don’t know yet,” Bowles said. “We have a lot of young guys that we’re trying to develop. So if there’s something out there that catches our eye, we’ll sign him. If not, we’ll stick with the guys we have. All options are open.”

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Notes & quotes: Bowles hasn’t decided which quarterback will start against the Titans. However, the reps among Josh McCown, Christian Hackenberg and Bryce Petty were divvied up differently Monday. Hackenberg (10-for-21, one touchdown) had six reps with the starters, his highest total of camp, and had eight more total reps than McCown (6-for-13, one touchdown). But the majority of McCown’s practice work was with the first-team offense. Petty (3-for-7) had 10 reps total . . . Running back Bilal Powell (sore neck) and linebacker Lorenzo Mauldin (sore back) were held out, but running back Matt Forte (hamstring) and rookie safety Jamal Adams (ankle) returned to practice.