For years, Peralta, 29, toiled as a starter with the Brewers. There was that one breakthrough season in 2014, when he went 17-11 with a 3.53 ERA.
But over the next three seasons, Peralta never found that consistency again and last offseason he and the Brewers parted ways. The Royals, intrigued by his 97-mph fastball, took a chance on a one-year, $1.5 million deal with a $3 million team option in 2019. The club did so with the notion of converting him to the bullpen.
But even manager Ned Yost and his staff had no idea Peralta would adapt so well to the closer's role. Entering Saturday, Peralta had lowered his ERA to 2.70 and was 6-for-6 in save opportunities.
"He's been very good," Yost said. "He was given an opportunity and he grabbed it. It's my experience that when you present an opportunity like that, someone will step up and grab it. He did."
Peralta made the adjustment fairly quickly, having to learn how to prepare his body to pitch on back-to-back nights and eventually, multiple games in a row.
"The hardest part is being consistent," Peralta said. "It's the way you prepare yourself. It's different. You have to be ready all the time. It's not like starting where you pitch and you sit for a few days."
The other big difference, Peralta noted, is the pressure. Getting the final three outs in a save situation is quite the adrenaline rush, he said.
"If you're not good, you lose the game for your team," Peralta said. "When you're starting and you have a bad inning, you can come back right away and be better. But now, you have a bad inning, you lose. And numbers-wise, one bad outing can set you back a month [in terms of ERA]."
Does Peralta feel that pressure?
"I know it's there, but I don't really feel it when I'm out there," Peralta said. "You know sometimes, you're going to have a bad outing. But you have to have a short memory."
Peralta views the switch to the bullpen as a potential career changer.
"It is more fun doing what I do now," he said. "I feel like every night you go out there, you can change the game. When you're in the rotation in between starts, you just hang in the dugout and cheer for the team. This is more fun."
Peralta's solid performance in the closer's role may even affect how the Royals view their team option on him in 2019, though that decision is far down the road.
"Of course, I love it here," Peralta said. "It's a great group of people here, coaches, front office. We all try to help each other."