NEW YORK -- For Brandon Nimmo, the sense of relief is apparent. Nimmo learned earlier this week that he has a bulging cervical disc pushing on a nerve in his neck, and that he is suffering from the effects of whiplash. He received a medical steroid injection to reduce the inflammation in his neck and, while none of that is wonderful news for the Mets’ Opening Day leadoff hitter, Nimmo is happy simply to understand what is wrong with his neck.

“I’m 26 years old. I had never had neck problems like this before,” said Nimmo, who went on the injured list earlier this week with what the Mets termed only as inflammation. “I take a lot of really good care of my body to try and prevent that stuff from happening, to warm it up. And so I was just like, ‘Man, why does this keep happening?’”

Nimmo’s neck woes date to what seemed like a relatively innocuous collision with an outfield wall April 14 in Atlanta. Two days later, Nimmo was in enough pain that the Mets removed him from a game in Philadelphia after only one inning. Nimmo missed two additional games before returning, presumably at something close to full strength.

But every few days, his neck pain resurfaced, likely playing a role in the .171/.312/.224 slash line he produced in 26 games since that time. This past Tuesday, Nimmo felt pain simply lifting his head off his pillow. He commuted to Citi Field and attempted to loosen his neck, but could not even turn it to the right without spasming.

“It hurt like hell,” Nimmo said.

A day later, the Mets placed Nimmo on the IL with a “stiff neck,” clarifying later that his injury was “neck inflammation.” Nimmo revealed Saturday that the issue is actually a bulging disc and whiplash. He is working with team chiropractor Dr. Wayne Winnick to resolve the latter issue.

Because the disc is not ruptured, Nimmo said, he is not at risk for needing surgery.

Still, the injury will take time to heal. Nimmo plans to refrain from all activities until he regains full range of motion in his neck, at which point he will ease into his rehab. There is no timetable for his return. While Nimmo heals, the Mets are relying on a platoon of Juan Lagares, Carlos Gomez, J.D. Davis, Rajai Davis and Aaron Altherr in the outfield. Michael Conforto, who is recovering from a concussion, is due back Sunday, while Jeff McNeil is first eligible to return in early June.

Conforto closing in on return

Although Conforto hoped he could return from the seven-day IL on Saturday, Mets officials were more conservatively targeting Sunday for his return. Major League Baseball still must approve Conforto’s return from a concussion, but he said he hopes and expects that to happen on Sunday. Manager Mickey Callaway agrees.

“We’re hopeful for that,” Callaway said. “He had a pretty strenuous baseball activity day [Friday], came out of it really well. We’ll do that again today, and then reassess where he’s at in the morning.”

Conforto was batting .271 with nine home runs before the May 16 collision with Robinson Cano that resulted in his concussion.

Roster move

To clear space for starting pitcher Jason Vargas, who came off the IL on Saturday, the Mets optioned infielder Luis Guillorme to Triple-A Syracuse. That rebalanced their roster, with 13 pitchers and 12 position players.

Todd Frazier will serve as the Mets’ backup shortstop in an emergency, Callaway said.