ATLANTA -- Brandon Nimmo’s neck woes, which began in April, are going to sideline him for a much more significant period of time than the Mets initially expected. The team is shutting Nimmo down from all baseball activities for 30 days, manager Mickey Callaway said Tuesday, after which point doctors will reevaluate him.

Nimmo received that recommendation from Dr. Robert Watkins, a Los Angeles-based spinal expert who gave him a second opinion earlier this week. Watkins confirmed the diagnosis of a bulging disc in Nimmo’s neck, likely the result of a collision with the SunTrust Park center-field fence on April 14.

“That’s certainly a loss for us,” Mets outfielder Michael Conforto said. “We were hoping to get him back up until last week or a couple of days ago. So hopefully, he’s got everything he needs to be on the path to getting back late in the year. For now, we’ve got to keep moving forward without him.”

That means giving at least some of Nimmo’s center-field reps to Conforto. Given that Nimmo will be sidelined until at least August, and possibly longer than that, the Mets are considering an alignment of Jeff McNeil in right field, Conforto in center and a mix of Dominic Smith and J.D. Davis in left. That will allow them to field a superior offensive lineup than one with either Juan Lagares (.533 OPS) or Carlos Gomez (.650 OPS) in center.

Conforto hasn’t played center field this year, but he has shagged fly balls there during batting practice and played 58 games (56 starts) at the position last season.

“I feel comfortable out there in center,” Conforto said. “Hopefully, it’s like riding a bike.”

Like many, Conforto’s thoughts on Tuesday were mostly with Nimmo, who complained of neck stiffness for the first time on April 16 -- two days after his collision in Atlanta. At the time, the Mets downplayed Nimmo’s injury, calling it a stiff neck and holding him out only two games. But Nimmo’s neck pain kept flaring up as he hit .171/.319/.224 from that point until May 20. Two days later, on May 22, the Mets placed Nimmo on the injured list with what they termed inflammation. Nimmo later clarified that he was suffering from a bulging disc and the effects of whiplash.

He said at the time that he should not need surgery, and Callaway confirmed Tuesday that the Mets still don’t believe Nimmo will. Still, the Mets will be without Nimmo, their leader in on-base percentage and position-player WAR last season, for a significant amount of time.

“You come into the season, you count on [Nimmo],” Callaway said. “His on-base percentage is such a helpful way for you to score runs. But we covered ourselves with depth, and we need that depth to step up and continue to play good baseball.”

Familia sidelined

A day after one of his worst outings in a troubled season, Jeurys Familia landed on the injured list due to a reoccurrence of a Bennett lesion in his right shoulder. In a bullpen shakeup, the Mets called up two relievers, Stephen Nogosek and Daniel Zamora, and they optioned Drew Gagnon to Triple-A Syracuse.

As recently as Tuesday afternoon, Callaway said that Familia’s “stuff is in the right place” when asked about the setup man’s health. Two hours later, the Mets placed Familia on the IL with the same injury that sidelined him from May 1-14 -- essentially a bone spur that has affected him for years. Upon returning, Familia allowed 14 runs in 13 1/3 innings -- including three in one-third of an inning Monday against the Braves -- to bloat his ERA to 7.81.

The Mets signed Familia this winter to a three-year, $30 million contract, and they have paid out only about $3 million of that money to date.

To replace Familia on their active roster, the Mets called up Nogosek, one of three relief prospects they received from the Red Sox for Addison Reed in July 2017. Nogosek, 24, recently earned a promotion to Syracuse, pitching 12 2/3 consecutive innings there without allowing an earned run. He will make his big league debut.

Zamora also returned for his second stint with the Mets, replacing Gagnon, who had allowed eight runs in his last three innings. The Mets as a whole entered Tuesday’s play ranked 28th in the Majors with a 5.47 bullpen ERA.

“We’ve got to recalibrate what we’re doing,” Callaway said. “We have to do the job better. That’s just plain and simple.”

Wilson scratched

Reliever Justin Wilson, who appeared to be days away from rejoining the Mets, was scratched from a rehab appearance Tuesday with Triple-A Syracuse due to left elbow tightness.

Wilson has twice been on the disabled list due to a sore left elbow, which has bothered him since April. He began a throwing program last month and said he felt much better than the previous time around, when he returned to the Mets for a single appearance before landing back on the injured list. Before he was scratched, Wilson was scheduled to make his fourth and likely final Minor League rehab appearance on Tuesday.

Signed to a two-year, $10 million contract this winter, Wilson owns a 4.82 ERA in 10 appearances.