Andrew Benintendi called teammate Cole Sturgeon late Monday night.

“I’m going to Seattle,” Benintendi told him.

Sturgeon paused, wondering who the Red Sox acquired from the Mariners in a trade for Benintendi.

“Then I realized (the Red Sox) were playing in Seattle,” Sturgeon recalled later. “I said, ‘man, that is awesome.’ “

Benintendi’s locker at Hadlock Field was empty Tuesday, but not because of a deal made on Monday’s trade deadline. Benintendi, 22, was called up to the Red Sox. He was officially added to the roster Tuesday and is expected to start in left field Wednesday.

Benintendi made his major league debut Tuesday, pinch-hitting for Bryce Brentz in the seventh inning and grounding out to second. He remained in the game to play left field and struck out to end the Sox’ 5-4 loss in his second at-bat.

The seventh overall pick in last year’s draft, out of the University of Arkansas, Benintendi is in the majors in his first full pro season. That has not happened with a Red Sox prospect since reliever Cla Meredith, a 2004 draft pick, was called up briefly in May 2005 for three appearances.

Benintendi has played only 151 minor league games with 570 at-bats and a career average of .312/.932 OPS.

“My only concern was (the limited number of) at-bats in the minor leagues,” Portland Sea Dogs Manager Carlos Febles said. “I think it came up sooner than I expected.

“At the same time, they won’t lose much with him. He will play good defense and run the bases … Everybody knows he can hit. All he has to do is make the adjustments, like everybody has to do when they get to the big leagues.”

When Benintendi was promoted to Portland on May 16, he got off to a slow start, batting .213/.531 the rest of the month.

Benintendi’s June numbers: .305/.886.

Then, in July: .329/1.042.

“If you saw him when he first got here, you saw the struggles, which is part of it,” said Sturgeon, who was Benintendi’s roommate on the road. “He came out of it good. I think it prepared him for what he’s going to face up there.

“His approach to the game is very relaxed and I think that allows him to – even when he’s struggling – to get out of it quick. He never really presses.”

In Benintendi’s last game on Sunday, he was 4 for 5 with two home runs and five RBI. He wowed even his teammates.

“I had a conversation about him with (Yoan) Moncada, saying ‘what the heck is he doing here? He’s making the league look so easy,” said shortstop Mauricio Dubon.

Moncada, of course, is the other big-time prospect that arrived in Portland this season (June 21). He said Benintendi’s promotion has no effect on him.

“Good for him. He’s a good teammate,” said Moncada (with Dubon interpreting). “When my time comes, it’s going to be my time.”

While Moncada, 21, is thought to have even more potential than Benintendi, Moncada needs more development. Moncada arrived from Cuba and did not play for over a year before signing with Boston almost 18 months ago.

Moncada, a switch-hitter, is batting .289/.931, but is struggling against left-handers (.158/.483 in 19 at-bats).

Benintendi bats left and has actually batted better against left-handers (.326/.900). His overall numbers in Portland were .295/.872, with eight home runs in 237 at-bats.

“He can swing the bat, use all fields with pop,” said Sea Dogs hitting coach Jon Nunnally said. “Once he got to know pitchers, he adjusted well. The way he adjusts, I don’t see him struggling.”

Nunnally said the biggest progress Benintendi made in Portland was as a fielder – “getting the baseball back in quicker.” Benintendi’s arm is not as strong as Boston outfielders Jackie Bradley Jr. or Mookie Betts, but his fielding is fine. His experience as a left fielder began only recently, and for only four games.

Once it became clear that Benintendi would not be involved in a trade on Monday, the speculation on his promotion to Boston began. Red Sox President Dave Dombrowski alluded to the possibility last month.

Febles found out Monday night while he was in a theater watching the Jason Bourne movie.

“They called me near the end of the movie,” Febles said. “I couldn’t watch the end … but it was worth it.”

Febles, in his first year as a Double-A manager, was given the job of informing Benintendi.

“It was a special moment to be on the phone with a guy,” Febles said, “and telling him he’s going to the big leagues.”

BOSTON’S NEED FOR Benintendi developed after left fielders Chris Young (hamstring) and Blake Swihart (severely sprained ankle) went down, and the Red Sox’s desire to move Brock Holt from strictly an outfielder to his previous utility role.

Boston has used right-handed hitting Bryce Brentz – who started Tuesday night’s game – but he is batting only .273/.674.

Manager John Farrell said the initial plan is to platoon Brentz and Benintendi. There is no timetable for the return of Young or Swihart.

BENINTENDI’S IN-SEASON promotion from Double-A to the Red Sox is the first one since Josh Reddick on July 31, 2009.

Jackie Bradley Jr. finished the 2012 season in Portland and began 2013 with Boston (after a hot spring training and an injury to David Ortiz, with various outfielders serving as the DH). When Ortiz was activated on April 19, Bradley was sent to Triple-A Pawtucket.

Other Sea Dogs to skip over Triple-A for their major league debut included pitcher Justin Masterson (2008), pitcher David Pauley (2006), pitcher Devern Hansack (2006) and shortstop Hanley Ramirez (2005).

Benintendi – whose 22nd birthday was last month – is not the youngest Red Sox prospect to get a promotion to the big leagues. Betts, who was drafted out of high school, was promoted in 2014 when he was 21 (his birthday is in October).

Bogaerts, an international free agent when he was 16, reached the Red Sox in 2013, when he was 20 (his birthday also being in October).

While Betts arrived when Boston was struggling at the bottom of the American League East, Bogaerts joined a contender and ended up starting in the World Series.

RISING FROM CLASS A to the majors in one year is rare, although New York Mets outfielder Michael Conforto did the trick last year, ending up in the World Series.

MONCADA CONTINUES to play second for the Sea Dogs. Barring an injury to Dustin Pedroia in Boston, Moncada is not going to the majors at that position. He may be seeing action at third base and/or the outfield this season – or not.

“He’s been taking ground balls at third and shagging fly balls (in the outfield),” Febles said. “Whether he does that in a game (this season), it remains to be seen.”

Moncada is not concerned.

“I played short, third and center field (in Cuba),” he said. “It’s like riding a bike.”

Kevin Thomas can be reached at 791-6411 or:

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Twitter: @ClearTheBases