Even if fans are not paying attention at Hadlock Field, when Rafael Devers swings his bat and connects, they notice.

Hard to ignore that smack.

“The ball comes off his bat differently,” said one scout, who has seen plenty of Devers. “Balls get to the outfield fast, even when he doesn’t square up a pitch.

“You can’t teach that.”

Devers, 20, is one of those naturals. He is the top prospect in the Red Sox organization and currently plays third base for the Portland Sea Dogs. He is batting .333 with a .982 OPS. His six home runs are tied for the Eastern League lead.

Devers’ sixth homer came in the first game of a doubleheader Saturday, when he swatted a change-up to center for a grand slam. It traveled an estimated 426 feet and had an exit velocity of 103 mph.

“It’s been an impressive start,” said Ben Crockett, the Red Sox director of development. Last year Crockett watched Devers struggle terribly early in Salem, only to finish with a .282 average and .779 OPS.

Devers’ defense has been solid this year except for three errors. He’s manned the position well.

Impressive offense and a good-enough glove … I know what you’re thinking. Why doesn’t Boston call him up?

Makes sense, right? The Red Sox’s weakest position, by far, is third base. Half of Boston’s 26 errors have come at third, and Boston’s offensive production from third base (.614 OPS) is the worst in the American League.

And here you have Boston’s best prospect tearing up Double-A pitching.

Boston’s simple answer is he needs more seasoning.

“He needs to continue to work on his offensive consistency and pitch selection at the plate,” Crockett said. “He continues to be really proactive defensively, getting his work in every day.”

With Pablo Sandoval, Marco Hernandez and Brock Holt on the disabled list, Boston is relying on Josh Rutledge for the moment.

Having a left-handed hitting Devers in Boston is tempting. He’s got the pop and an all-field approach that would hammer the Green Monster.

“We like him a lot. He’s having a great season,” said Dave Dombrowski, the Red Sox president. But “he’s in Double-A at 20 years old right now. We’re happy where he is right now.”

Not right now? But later.

Maybe later this season?

Devers understands that two of his Class A Salem teammates last season, Andrew Benintendi and Yoan Moncada, reached Portland last year on their way to the majors. And while Moncada was traded to the White Sox (where he’s having a solid year in Triple-A), Benintendi is established in the Fenway outfield.

But Benintendi was a more polished player last season. He had two years of college ball before going pro and was 22 when he was called up last summer.

For a better comparison, remember when another 20-year-old from the Caribbean was a touted prospect in Portland?

Xander Bogaerts finished the 2012 season with 23 games in Portland as a 19-year-old. Bogaerts began 2013 in Portland, batting .311 in 56 games, before being promoted to Pawtucket, then reaching the majors in August. Bogaerts was Boston’s starting third baseman in the World Series.

Devers is aware that he’s close to the majors.

“I think about it but it’s not my decision,” Devers said through an interpreter. “I just want to play hard.”

Devers, from Sanchez in the Dominican Republic, has been playing baseball since he can remember. When he was a teenager, the pro scouts took notice.

“That’s the goal for a lot of Dominicans,” Devers said.

At age 16, Devers signed with the Red Sox for a $1.5 million bonus in 2013.

Devers, who rose through the system in the shadow of other prospects, like Bogaerts, Mookie Betts, Benintendi and Moncada, has emerged as one of the few top prospects not traded by Dombrowski.

There’s a reason the Red Sox are holding onto him.

“He’s special,” Sea Dogs hitting coach Lee May Jr. said. “He’s got a natural swing. He has a good understanding how his swing works and how he needs to attack the baseball. When you get to this point, it’s less about your mechanics and more about your approach.

“We’re watching the maturation of pretty good hitter.”

The approach is still being polished. Devers has struck out 17 times – not excessive but he has chased some poor pitches.

“Teams are adjusting to him, trying to get him to expand the zone,” Sea Dogs Manager Carlos Febles said. “He was swinging at pitches that were balls.

“This is a learning process for him, and he has a better understanding.”

Devers’ play at third “is pretty good,” according to Febles.

“He needs to play a little faster at times, understanding the speed of the runner. Sometimes he plays a little too deep. (Manny) Machado plays deep but he has an unbelievable arm.”

Not having a cannon arm like Machado is certainly not a knock on Devers. But he needs to fine-tune his play.

And Devers needs to watch his weight. The Red Sox media guide lists him as 234 pounds.

“No,” Devers corrected without needing an interpreter. “I’m 225.”

Devers has slimmed down, but the concern about an overweight third baseman is understandable, given the struggles with Sandoval’s physique.

“We need to keep an eye on him,” Febles said. “The players are weighed twice a month but I want to make sure he weighs in once a week. We need to know where he’s at.”

For now, Devers is at the doorstep to the major leagues. Some more seasoning and the kid could be helping the Red Sox sometime this summer.

Kevin Thomas can be reached at 791-6411 or:

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Twitter: @ClearTheBases