Chaim Bloom never wanted to say the Boston Red Sox were rebuilding. The team’s chief baseball officer spent the offseason explaining the decisions to further dismantle a World Series-winning outfield, to rehire Manager Alex Cora a year after he fired him when Cora’s role in a cheating scandal became clear and to spend selectively on the free agent market when his roster had obvious holes.

He warned against counting the Red Sox out, the kind of thing a front-office executive says to a grizzled baseball city to head off frustration — even though grizzled baseball cities usually see right through that. He assured reporters that the team intends to win as many games as possible. He delivered the requisite offseason platitudes about a World Series title always being the goal.

“I would hope that no matter how this year goes, even if it ends with us popping champagne, for me I would love to get to the end of this year and be able to see that next core,” Bloom said during spring training, “… that next core that is going to be the center of a sustainable championship contender, to see that core taking shape.”

In other words, this was supposed to be the year Red Sox fans got a glimpse of the future, a year spent navigating angst and frustration tempered only by the promise of what may be next. This was not supposed to be the year Red Sox fans fell in love again.

But just three weeks into the season, their remodeled Red Sox are in first place in the always rough-and-tumble American League East, complete with a personality all their own — a gritty roster with fewer big names than usual, a team that has matched up well with last year’s pennant winners and this year’s pennant favorites and AL East competition, too. Entering play Thursday, they were tied with the upstart Oakland Athletics for the most wins in the American League, second only to the mighty Los Angeles Dodgers for most in the majors.

The Red Sox are not the only team exceeding expectations with a strong start. After opening with six losses, the A’s have won 11 straight games to charge to the top of the AL West. Close behind them are the Seattle Mariners, who were supposed to be a year or two away but look ready to emerge as a pest this year. The Mariners begin a four-game series at Fenway Park on Thursday.

And while the Chicago White Sox seem built to contend for the pennant, they are chasing the Kansas City Royals in the AL Central. The low-budget Cincinnati Reds have emerged as a legitimate force in the wide-open National League Central. The San Francisco Giants have elbowed their way into second place in the NL West, between the Dodgers and San Diego Padres.

But the Red Sox, not exactly used to sneaking up on people, are sneaking up on almost everyone.

“This atmosphere that we have right now, it’s definitely fun to come to the ballpark every day, show up and have fun with each other,” shortstop Xander Bogaerts said after his team beat the Toronto Blue Jays on Tuesday. “We’re definitely enjoying ourselves, enjoying the moment, and hopefully we can just continue this for a long time — for the whole season if we can keep it up.”

Bogaerts is one of the holdovers from the 2018 World Series team, one of a handful of players Bloom sees as part of the old core as well as the new one. Bogaerts, injured ace Chris Sale, non-injured ace Nathan Eovaldi, third baseman Rafael Devers and starter Eduardo Rodriguez are among those who remain, survivors of a small-scale teardown that included sending annual MVP candidate Mookie Betts to the Dodgers, shipping left fielder Andrew Benintendi to the Royals and letting Gold Glove-winning center fielder Jackie Bradley Jr. walk to Milwaukee.

Bogaerts spent part of Tuesday’s win with his backside in a laundry cart hurtling through the dugout under a tunnel of his teammates being bombarded with high-fives. It’s a ritual that has become habit for this Boston team, one of those celebratory routines that seem to signal some level of camaraderie — or at least that signal a team is far from resigned to six months of angsty mediocrity.

Outfielder Alex Verdugo, the big name that came back to Boston in the Betts deal two winters ago, also seems likely to be a key part of that next core. The 24-year-old with a .290 career average in 200-plus games is a ball of confidence and energy, the kind of guy who chats with fans between innings and doesn’t apologize for believing he can be better than anyone he is facing. He and 26-year-old slugger Franchy Cordero, both acquired in deals for former Red Sox outfielders, could be important parts of that Boston lineup for a long time. Bobby Dalbec may join them; the Red Sox hope the 25-year-old first baseman can emerge as a reliable offensive producer for years to come.

But if Bloom’s offseason aversion to the word “rebuilding” seemed rhetorical at times, some of his moves suggested a genuine expectation of more immediate success. Instead of trading away every valuable piece and filling in with low-cost youngsters all over the field, the Red Sox signed the kind of players whom playoff teams covet — versatile, experienced veterans who can help teach a talented young team how to win.

They surprised some by signing veteran utility men Enrique Hernández, a longtime Dodgers stalwart, and Marwin Gonzalez, a veteran of many Houston Astros playoff runs, both of whom can play all over the infield. They bet low on former Tampa Bay Rays outfielder Hunter Renfroe, a sneaky good defender with World Series experience who brings prolific power. They also picked up veteran starter Garrett Richards and made quiet-but-sturdy additions to their bullpen in Adam Ottavino and Matt Andriese.

“I think experience and being in that situation and winning, I think it helps a lot, but it helps in a lot of little things. It’s not something where it’s like: ‘Oh, we’ve got some winners now. It’s going to turn right away,’ ” Hernández said. “. . . I think the presence is the most important thing. Having guys like us that you can lean on us when times aren’t going great or whatever. So far, we’re having a lot of fun.”

And while the Red Sox may not be loaded with as many big names as usual, they still have a bona fide star in designated hitter J.D. Martinez, whose down year in 2020 coincided with the team’s first last-place finish in the AL East since 2015. Everyone around the Red Sox — and everyone familiar with Martinez’s meticulous approach to hitting, for that matter — seemed certain he would reemerge as one of the game’s best hitters in 2021.

Even with a coronavirus scare that forced him away from the stadium for multiple games, Martinez entered Thursday leading the AL or tied for the league lead in hits, home runs, RBI and total bases. The Red Sox led the majors in on-base-plus-slugging percentage, runs and hits. And as if all that weren’t enough to make the Red Sox believe their fortunes may be turning sooner than expected, the New York Yankees, thought to be the class of the AL East, sat in last place, tied for the fewest wins of any team in the majors.

“To win some ballgames and actually be at the top of the standings and kind of, like, overlooked a little bit, I love it,” Verdugo said. “I love this group of guys. I love this team. The chemistry, everything, it’s something special on this team.”