SURPRISE, Ariz. -- It was late 2006, and Rene Francisco, the Royals' assistant general manager of Major League and international operations, was taking his first trip to the Dominican Republic after joining Kansas City six months earlier.

The Royals were holding a workout at their academy in Salcedo, getting a look at some top prospects from around the area. After the players invited to the workout finished their tryout, Francisco was meeting with some of the Royals coaches at the academy when a scout walked up to him and said there was a young kid with a good arm who threw after the workout. The Royals might want to check him out.

So Francisco and his group went back to the field and watched a small, skinny pitcher -- just 5-foot-9 -- throw. Francisco was impressed by this pitcher’s quick arm, the spin on his ball and the competitiveness he showed on the mound. He made a quick verdict: Sign him.

“And that’s the story of signing Kelvin Herrera,” Francisco said last week.

Over the next decade, Herrera grew from the 17-year-old pitcher who signed for just over $15,000 after an unexpected tryout to one of the best relievers in baseball. After 10 seasons in the Majors, the right-hander announced his retirement last week with a Twitter post that started with “Thank you, baseball.”

His retirement resonated throughout the Royals organization because of what he meant to the club, both as a pitcher and person. Hererra, still just 31 years old, made his MLB debut for Kansas City at 21 in 2011, and from '12-18, the hard-throwing right-hander was one of the best setup men -- and eventual closers -- in the game. In '14, he posted a 1.41 ERA in 70 games for the Royals, following that up with a 2.71 ERA in 72 games the following year, earning his first of two All-Star Game selections. He was a key piece in the Royals’ 2015 World Series title, pitching three scoreless innings in the decisive Game 5 to allow the Royals to rally and force extra innings.

• Herrera calls it a career after 10 seasons

“He meant so much,” Francisco said. “He was small in stature, but had a big heart. His changeup was devastating. Just the aggressiveness, the lack of fear that he had on the mound. He’s fearless. He was always fearless on the mound.”

Herrera is part of Royals history: He is the postseason career leader in appearances (22) and strikeouts (38, tied with Wade Davis) and ranks third in ERA (1.26). But there was a time where he didn’t think he’d ever make it to the Majors. In fact, he was ready to quit.

While playing in Class A, Herrera’s arm started to hurt. The recovery process was long and challenging. Herrera was frustrated enough that during Spring Training one year, he visited Victor Báez, the Royals coordinator at their Dominican Baseball Academy, to ask whether he should give up on baseball.

“He was tired,” Báez said. “He wanted to quit. Thank god I was there at that moment because I had the opportunity to talk to him and to explain to him that it would be a bad decision at the time. He made the right decision and kept fighting. And as soon as he recovered, we made the decision to make him a reliever. And everything went really fast after that. He made the big leagues and then we went to the World Series, and everything changed for him.”

For many in the Royals organization, that’s what they remember most about Herrera, seeing him battle the frustration while rehabbing in Arizona for so long. When he made it to Kansas City, it all became worth it.

“He made the big leagues, got a chance and never gave it up,” Báez said. “He got an opportunity and never turned back.”

As Herrera grew older in Kansas City, his confidence swelled, and he found his voice in the bullpen along with Davis, Greg Holland and Ryan Madson. His daily preparation and work ethic inspired young teammates. The Royals bullpen was iconic in 2014-15, and Herrera was a key piece of that. Over eight seasons with Kansas City, Herrera posted a 2.75 ERA and 438 strikeouts in 441 1/3 innings.

And near the end of his time as a Royal, he embraced a leadership role among the young bullpen. When the Royals fell out of contention in 2018, he was dealt to the Nationals, then signed with the White Sox and Cubs over the last two years.

Kansas City, though, will always be the place where Herrera grew up.

“He’s a very special part of Royals history,” general manager Dayton Moore said. “We’ve watched him grow as a player and a person to become a terrific husband and father. We’re really proud of him for what he’s been able to accomplish.”