CLEVELAND – Jake Mauer fondly remembers his first season as manager of the Class A Cedar Rapids Kernels, back in 2013.

"It was like a manager's dream team — four solid [future] major leaguers up the middle," Mauer said.

Those Kernels had Byron Buxton in center field. Jose Berrios, an All-Star for two seasons now, was on the mound every fifth day. And in the infield, along with current Tigers utility man Niko Goodrum, Mauer was managing the man who on Tuesday night will be the starting shortstop for the American League All-Star team.

The weird thing? Jorge Polanco usually was the Kernels' second baseman.

"I knew he could handle shortstop, he was a good enough athlete. But I thought he was going to become an elite, All-Star-level second baseman," said Mauer, who sent Goodrum to short 81 times and Polanco 49, mostly when his teammate was injured. "It's a testament to Jorge that he worked to make himself better and stayed at short. I'm really proud of him."

Polanco, a year after suffering the embarrassment of failing a steroids test and serving an 80-game suspension, finally has plenty to be proud of, especially at the plate. He not only leads the Twins in hits with 111, but he also has 24 more than any other teammate. And 41 of them are for extra bases, which ranks eighth in the league, one behind Max Kepler. He has the team's best batting average (.312) and best on-base percentage (.368).

"With a bat in his hands, he's a beast, man," said teammate and fellow infielder Ehire Adrianza.

Revolving door at short

But it wasn't always easy convincing his team that he was a natural heir to his fellow natives of San Pedro de Macoris, the Dominican city once known as "The Cradle of Shortstops" for producing infielders such as Rafael Ramirez, Tony Fernandez, Alfredo Griffin, Jose Offerman and Julio Franco. Twins scouts and executives saw a different San Pedro role model for Polanco: Robinson Cano, a second baseman.

"There were questions about his foot speed and his arm strength when he came through. But remember, he was just 19 then, and we're just trying to figure out what he's going to be in four or five years," Mauer said. "He had maybe an average arm for a shortstop, but a great one for second base."

The Twins, who used 11 different Opening Day shortstops in a 12-year span from 2006-17, tried to address their problem at the position by drafting Nick Gordon and Royce Lewis, and signing Wander Javier, and trading for Eduardo Escobar. They didn't realize they had the answer on their roster, even when he reached the majors.

"When I got here [in 2017], some guys told me, 'Yeah, his defense, he's got to work on it, he's got to improve. Maybe he's second base when [Brian Dozier] leaves," said Adrianza, who has backed up Polanco for the past two seasons. "But he works so hard, and he's been getting better and better. You don't hear anyone say [he's not a shortstop] anymore."

"I saw him in the Dominican [winter] League playing second base, never much at short," said Tony Diaz, hired last winter to coach the Twins' infielders. "I watched some videos when I got to Minnesota, and I was impressed. He's more than capable. Good hands. Some inconsistency with the throws, so we addressed that."

'A better rhythm now'

He did by emulating Fernandez, one of the best infield gloves in modern baseball history. Fernandez famously did not throw overhand, instead relying on shorter, swifter mechanics that approach sidearm. Diaz introduced the motion to Polanco in Fort Myers, first by showing him a six-minute highlight video, and the adjustment has made a difference.

"He's got a more consistent [arm] slot for his throws, a better rhythm now. He can throw with velocity and still be accurate," Diaz said. "He prepares as well as anybody. I know how much pride he takes in his preparation, almost as much as the results."

So is he definitely a shortstop now? For good?

"The main thing is to keep working continuously, and not let any hesitation or thought about the position get into the way. Wherever the team is going to place me, I'm going to keep doing my best," Polanco said. "They mentioned that at some point there would be some changes and adjustments, but the last three years, they haven't mentioned it again."

Maybe it's time to aim even higher, then.

"I told him, 'Now you're an All-Star shortstop,' " Adrianza agreed. " 'Your next goal is to be a Gold Glove.' "