NEW YORK -- The Mets’ depleted outfield suffered another blow on Wednesday, when the team placed Brandon Nimmo on the injured list due to a stiff neck. The club called up veteran Rajai Davis from Triple-A Syracuse to replace him, and reliever Paul Sewald was designated for assignment to clear space on the 40-man roster.

Nimmo was a late scratch from Tuesday’s lineup due to the neck issue, which initially began bothering him in April and never quite disappeared. He went on Tuesday for an MRI that resulted in a diagnosis of neck inflammation, according to a team official. The same official did not respond when asked about structural damage.

“It’s been off and on for four weeks now,” Nimmo said late Tuesday. “It would go away for a couple days and come back. … It’s like a sharp pain.”

Nimmo was hitting just .200 with a .667 OPS in 43 games -- struggles that neither he nor the Mets are willing to chalk up to the injury, but that manager Mickey Callaway nonetheless acknowledged may be related.

“If you’re battling something, it can affect it,” Callaway said.

The Mets are now left without the top four outfielders on their depth chart. Michael Conforto began light baseball activities on Wednesday as he continues recovering from a concussion, but the Mets have offered no timetable for his return. Jeff McNeil was out of the lineup on Wednesday due to a tight left hamstring, with hopes that he will miss only a day or two. Yoenis Céspedes is almost certainly done for the season after sustaining multiple fractures in his right ankle.

As a result of these injuries, the Mets found themselves scrambling on Wednesday to construct a healthy outfield mix. J.D. Davis, who did not take any outfield reps this spring, was the team’s starting left fielder against the Nationals. The Mets have also asked Dominic Smith to begin taking fly balls in left after declining his request to work out at the position during Spring Training. The Mets plan to rely on Davis, as well as Juan Lagares and Carlos Gómez -- the latter of whom was in Syracuse as recently as last week.

“Davis, today, is one of our starting outfielders, not by choice,” Callaway said. “That’s who we have. … Things don’t always go to plan, and you have to make adjustments along the way to be the best team we can possibly be.”

Like Gomez, Rajai Davis is a veteran the Mets signed this winter to provide depth in just this type of scenario. Davis continued his strong spring showing into the Minor League season, batting .277 with a .747 OPS in 37 games for Syracuse.

His contribution to his new club was immediate and impactful, as he belted a three-run homer in his first at-bat, helping the Mets to a 6-1 win.

Updated Edwin edicts

Less than eight weeks into the season, the Mets have abandoned their plans to limit closer Edwin Díaz to the ninth inning. Callaway said on Wednesday that the team is now open to using Diaz for four to six outs on occasion as a way to bolster the injury-laden bullpen.

“If we’re not going to be where we want to be at this point, how can we expect to be there and hold off on doing that with Diaz?” Callaway said. “We’ve got to win some games. We’re going to approach this like the playoffs, because we feel like we need to."

Following a win in Philadelphia last month, Callaway detailed strict rules for Diaz, who threw a career-high 73 1/3 innings last season for the Mariners. He said at the time he would never use Diaz for more than three outs, nor deploy him earlier than the ninth. The only exceptions, Callaway said, would occur in the playoffs.

Several days later, Callaway edited those rules to allow for more flexible usage down the stretch. On Wednesday he edited them again, detailing plans to use Diaz for multiple innings whenever it’s warranted -- a potential boon for a bullpen missing both Seth Lugo (right biceps tendinitis) and Justin Wilson (sore left elbow).

“Diaz all along has been open to anything,” Callaway said. “This kid can go out there and pitch three innings if you ask him to. So it’s never been about a conversation with him. It’s been more about, hey, we have this unbelievable asset that has done a certain job, and we have him for a long period of time, and we can win a lot of games while he’s under our control. How do you use him the right way to make him the best player he can possibly be?”

Last year, Diaz recorded three multi-inning saves, allowing one run in four innings on those occasions.