Boston Red Sox's Rafael Devers connects for a grand slam against the New York Yankees during the first inning of a baseball game, Saturday, June 30, 2018, in New York. Credit: Julie Jacobson | AP

He looks like a kid. Not when he plays, because at 6 feet and 237 pounds, Rafael Devers has a major league body that helps him blend in with teammates, all at least two years his senior. It’s in the locker room, where his face — the one that earned him the childhood nickname “Carita,” Spanish for “baby face” — often reveals a bright smile and belly laugh.

He acts like a kid. Not when he takes the field, where Devers — who returned from the disabled list Wednesday — plays a crucial position (third base) and helps anchor a fearsome lineup (hitting sixth or seventh) for the 80-34 Red Sox, the best team in baseball. It’s on the bus or at the hotel or in the dugout, where his humor provides momentary respites for a team challenging history in one of the nation’s most pressurized markets.

He is a kid. Devers, 21, would be one of the youngest players on Boston’s High-A affiliate in Salem, Virginia, but here he is this season, launching grand slams in Yankee Stadium and twice taking deep his childhood hero, Bartolo Colon. In his quick ascension, though, Devers experienced increasingly common stresses as players his age more frequently hit the majors. Devers left behind peers. He rotated through coaches. He battled homesickness along with the toughest pitching he’d ever seen, while consistently moving in a country and culture to which he was still adjusting.

“I’m trying to learn as fast as I can, but it’s hard,” Devers said last month.

“Carita” is the face of one of baseball’s new trends: Prioritization of youth. Devers is the 13th player this decade to appear in more than 150 games before his 22nd birthday, the most since the 1970s (20). Before 2020, with the rise of other young players, such as the Washington Nationals’ 19-year-old phenom Juan Soto, the trend could reach new heights, said Dan O’Dowd, the longtime Colorado Rockies general manager and now an MLB Network analyst. Similar changes in mindset have also affected the NBA draft, NFL free agency and coaching searches in college basketball and MLB.

“[Baseball] players become less valued in their mid- to late-30s, in some cases even early 30s,” O’Dowd said. “Now, [teams] put [more emphasis] on the promotion of younger talent at minimum dollars. . . . Most of the extra roster spots that used to go to [older] players now go to those with low service time and high upside.”

The allure of promoting Devers was that, in a data-driven era for sports overall and especially baseball, the numbers are still just what O’Dowd called “predictive analysis.” There’s no replacement for seeing a player play. That eternal truth helped accelerate Devers’s ascent to the majors while also increasing the pressure he first felt in August 2013, when the Red Sox signed him for $1.5 million.

Back then, his quick bat rocketed him through the minors and, in High A Salem, Devers met Deanna McNaughton, one of the English teachers and cultural liaisons the Red Sox, like many ballclubs, employ throughout their organization. McNaughton noticed in class that, even though he was shy, Devers often laughed at himself before anyone else could for a mispronunciation or unintended double meaning. In public, though, he retreated. As his rise continued — he started 2017 at Class AA Portland (Maine) — he got further from teachers and closer to full-time translators. Soon, the team would expect all his media appearances to be in English.

“He was afraid to take risks with the language,” McNaughton said. “He really kind of realized, I don’t want to say the gravity, but the potential [of the demands] in the major leagues.”

In Portland, Carlos Febles, the manager, understood this was the first high-intensity media situation for prospects in the Boston system. “A lot” of New Englanders, he said, drive to Portland or Class AAA in Pawtucket, Rhode Island, to witness the next big thing.

“[Boston] is a very demanding market,” said Febles, now the third base coach for the big league club. “It’s tough for the players that come in [from outside]. If you grew up in the organization, you kind of have an understanding how things will be in the big leagues . . . based on what you have heard in the minor leagues, especially when you go to Portland.”

In 77 games for the Sea Dogs, Devers batted .300 with 18 home runs. He was sent to Pawtucket, where he raked for nine games. Before the season, a veteran Red Sox reporter wrote it was “a little soon” to expect Devers in the majors that year. But as the playoff race had heated up, the Red Sox had a need for a third baseman, reportedly scouring the trade market for an established player. Finding the prices too steep, the team ultimately relied on their own predictive analysis.

In late July 2017, Devers made his MLB debut. He proved capable as the everyday third baseman — a .338 on-base percentage in 58 games, plus two postseason home runs.

“He’s a 21-year-old kid, but he belongs here,” said first-year Boston manager Alex Cora, who was a bench coach in Houston last season for the Astros’ World Series title — that included beating Boston in the AL Divisional Series. “We’ve been talking about it the last few weeks, that he’s skipped a few steps in player development, yes, he did; he’s learning at the big league level, he is; but at the same time, they needed him last year here.”

Like other nonnative English speakers, Devers relied on his translator despite grasping the language, because, at least in part, he didn’t want to reduce complex thoughts to simple phrases. He also still got nervous sometimes.

Devers practiced English by telling jokes or singing songs to teammates. Often, he wound up laughing at the attempts, as he used to in McNaughton’s class. Devers’s demeanor, combined with his attention to detail on the field, impressed teammates. First baseman Mitch Moreland, who had the locker next to him, grew particularly fond of Devers. They started taking batting practice together almost every day.

Moreland taught Devers about American music, including “Friends in Low Places” by Garth Brooks and George Strait, about whom Moreland told Devers, “This is the jefe right here.” Moreland saved his favorite, Eric Church, for the hitting cage.

“Raffy doesn’t have a choice,” Moreland said. “He’s going to be an Eric Church fan before you know it, I promise.”

Earlier this season, the Red Sox faced the Texas Rangers, Moreland’s old team. Moreland, Febles said, arranged a meeting between Devers and veteran Adrian Beltre, a Dominican third baseman who debuted in the majors at 19 and is now a surefire candidate for Cooperstown. They talked about life as a young player, missing home, the business of baseball and how to sustain success at this level. After the conversation, Febles noticed, Devers beamed.

Though it’s easy to forget, he has only played about one full season’s worth of games. To him, to his increasing contingent of peers in the majors, stress doesn’t dull the shine and hope of the big leagues. He shrugged off a question about his age.

“I don’t try to act older,” he said. “There’s always going to be pressure, and I think that if you love something, you’re passionate about something, you’re always going to have those nerves going out to the field. It doesn’t matter, if you’re me, if it’s opening day or the game tonight.”