He already had his world turned upside down once, so when Williams Jerez got the news about a career change with the Red Sox, he shrugged.

“I said OK,” Jerez said.

Jerez was an outfielder, drafted by Boston out of high school in the second round in 2011. But after three seasons the Red Sox changed their mind about Jerez and made him a pitcher.

“They made a good decision,” he said.

Apparently. Jerez, 23, began his professional pitching career with 34 innings last year and is zooming through the system, reaching Double-A Portland one month ago.

“I was surprised,” Sea Dogs pitching coach Kevin Walker said about getting Jerez. “It’s almost like he’s been doing this a long time. He’s caught on quickly and really opened some eyes.”

Jerez, who had only pitched briefly in youth leagues, has relieved in nine games for the Sea Dogs. He’s posted a 2.16 ERA with 13 strikeouts and seven walks in 162/3 innings. Lefties are batting .147 against him, right-handers .189.

Nice adjustment.

But Jerez handles change well – like when he was 17 and living in the Dominican Republic. His father brought him to New York City.

“My father said, ‘You need to go to school here.’ I said OK,’ ” Jerez recalled. “He said, “Do your best.’ “

And one more thing …

“Learn English.”

Jerez arrived, knowing how to say only a few words in English – and how to swat a fastball.

By the end of his junior year, Jerez learned the language and professional scouts knew his name.

After his senior year at Brooklyn’s Grand Street Campus High, where he batted .692 with five home runs, Jerez was invited by various teams to show off his skills. During one showcase with the Mets, he hit two home runs into the second deck of Citi Field.

The Yankees also had interest and reportedly planned to grab Jerez in the second round.

But Boston drafted seven picks ahead of the Yankees and selected Jerez, signing him for $445,000. He was going to the franchise that featured his favorite player, David Ortiz.

If you have not heard of Jerez, it may be because of other players drafted by Boston ahead of him – Matt Barnes, Blake Swihart, Henry Owens and Jackie Bradley Jr. – and behind him (Mookie Betts in the fifth round).

And because Jerez did not make much of a splash as a pro outfielder. Playing in the Gulf Coast League one year and in short-season Lowell the next two seasons, his numbers kept declining – to a .176 average/.439 OPS in 2013. He never hit a home run in three years.

“I didn’t do so well,” said Jerez, who was called into a meeting after the 2013 season.

“They said, ‘We want you to pitch because we know you have a good arm. You just need to throw strikes.’ “

Control has been one of the biggest obstacles, but Jerez has commanded his pitches well enough with room for improvement.

“He has flashed a really good fastball with life and a really tight slider,” Walker said. “Now it’s just working on being more consistent; facing hitters, getting more experience.”

That lively fastball, in the low to mid 90s, is Jerez’s strength. And it may be why he’s already here in Portland. After this season, Jerez is eligible for the major league Rule 5 draft and unless Boston puts him on the 40-man roster, some team may take a chance and take him for its major league roster.

“With a left arm that can throw that hard,” Walker said, “there’s a great chance that good things will happen with this kid.”

Kevin Thomas can be reached at 791-6411 or at:

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Twitter: ClearTheBases