BALTIMORE — There are relief pitchers who haven’t seen a batter’s box in years walking around the New York Yankees clubhouse these days wearing T-shirts with a four-word, all-caps phrase superimposed over an outline of the strike zone: “SAVAGES IN THAT BOX.”

The T-shirts miraculously materialized on the chests of the Yankees’ players just 24 hours after manager Aaron Boone’s infamous tirade to umpire Brennan Miller on July 18, in which he uttered that very phrase — modified by a certain vulgar adjective that starts with “f” and ends in “ing” — to make the very specific point that the team’s hitters are relentless about their at-bats.

But in the days and weeks since, the phrase has become an intrinsic piece of the Yankees’ identity — defining not just their hitters’ approach in the batter’s box, but the entire team’s mentality in the face of a bizarre and unending rash of injuries, their steely resolve in the face of the front office’s failure to acquire reinforcements at the trade deadline and, not least of all, their manager’s unrelenting, infectious, upbeat demeanor.

Aaron Boone, it is safe to say, is a savage in his positivity.

“Very calm. Never panics. Always a calm demeanor. Stays positive,” Yankees lefty James Paxton said. “If we have a rough stretch here and there, he has encouraging words. He’s been fantastic. ... ‘Savages’ was perfect. It’s a really good, one-word description of what this group is.”

“We see ourselves like that, 100 percent,” said veteran lefty CC Sabathia, currently on the injured list because of a sore knee. “You can see we’re all wearing the T-shirts.”

Monday’s snapshot of the Yankees, as they barreled into Camden Yards and pummeled the last-place Baltimore Orioles, 9-6, in the opener of a three-game series, told you just about all you needed to know about their season.

At 73-39 following Monday night’s win, their games above .500 (34) just barely outpaces their cumulative number of trips to the injured list (32, by 25 different players) this season. They were nine games ahead of second-place Tampa Bay in the AL East, and 14 1/2 games ahead of third-place Boston (16 games in the loss column), from whom they swept a four-game series at Yankee Stadium over the weekend.

The Yankees’ injured list grew by two over the weekend, with the losses of first baseman/designated hitter Edwin Encarnación (broken wrist) and center fielder Aaron Hicks (elbow strain), bringing its current population to 16, including seven former all-stars. Their best starting pitcher (Luis Severino) and top setup man (Dellin Betances) have yet to pitch this season, and their cleanup hitter (Giancarlo Stanton) has played in just nine games and hit just one homer.

On Sunday night, two more key Yankees were lost to injuries, as second baseman Gleyber Torres left the game because of what was described as a “core issue” — with the team sending him to the hospital for tests — and third baseman Gio Urshela was removed a few innings after fouling pitches off both legs.

But Monday brought, of all things, good news. Neither player needed to go on the IL, and Torres was even back in the lineup, going 0 for 5 at DH and thus sparing them the ignominious distinction of having every player in their opening day lineup go on the IL at some point. (True: Opening day starting pitcher Masahiro Tanaka also has not been on the IL, but he has been pitching with a torn elbow ligament.)

It says something about the current Yankees that the potential loss of Urshela — a former middling prospect and fringe big leaguer who is playing only because incumbent third baseman Miguel Andújar is out for the season — would be looked upon as a crippling blow, given his .882 OPS (on-base plus slugging).

But there is a certain savagery in the way the Yankees have risen above every new injury — pressed-into-duty reserves Mike Ford and Mike Tauchman powered Monday night’s win — and a certain savagery in the way Boone consistently turns the incessant injury talk around to praise the players who have stepped in.

“I don’t think you can say enough,” Boone said Monday, “about the meaningful contributions we’ve gotten from so many guys.”

Boone’s savage positivity extended to the days and hours following the July 31 trade deadline, when the front office essentially stood pat — a shocking result that bucked every expectation across the industry, where the Yankees were viewed as major buyers for starting pitching. The team’s lack of a signature move stood in stark contrast to the Houston Astros, the team they are battling for supremacy in the AL, who added veteran ace Zack Greinke to what was already one of the top rotations in the league.

Rather than question his own front office and bemoan the state of his rotation, which put up a 6.18 ERA in July and still has major holes, Boone pronounced his team “ready to roll” with what they had.

“We know we have everything we need to be a championship club,” he said. “Nothing changes there.”

Two more months of this, and Boone, 46 years old and in his second year on the Yankees’ bench, may walk away with the AL’s manager of the year award. It would be well-deserved — despite voters’ traditional preference for skippers of small-market teams that rise above modest expectations. Last year, for example, Bob Melvin, manager of the 97-win Oakland Athletics, won the award over Alex Cora, who merely took the Red Sox to a franchise-record 108 wins as a rookie. But one key difference: Cora’s Red Sox never dealt with the sort of injuries the Yankees have.

“Absolutely,” Paxton said when asked about Boone’s award credentials. “Our ace [Severino] hasn’t pitched all year. Giancarlo has barely played. Dellin Betances, out all year. Some of our guys have been on the injured list multiple times. And we’ve still found a way to put ourselves in the position we’re in. And a lot of that is because of [Boone’s] presence and the way he’s led this team.”

There is plenty of credit to go around in this remarkable Yankees season, from the front office that found the players — including some, like Urshela, off the game’s trash heap — to the players who have done the heavy lifting on the field. But Boone, with no contriving and no false notes, gave the Yankees their T-shirt-worthy identity.

They are savages not only in the box, but also on the mound, in the outfield gaps and, more times than they would prefer, even in the trainer’s room.