The Royals’ monthslong effort to replenish their farm system continued Monday evening, as they traded closer and eight-year veteran Kelvin Herrera to the Washington Nationals.

In their second trade of the month, the Royals acquired a trio of minor-league players: third baseman Kelvin Gutierrez, outfielder Blake Perkins and right-handed pitcher Yohanse Morel.

But in the process, they parted ways with the last remaining piece of the vaunted bullpen that terrorized baseball throughout two playoff runs and the 2015 World Series championship.

Herrera, a 28-year-old from Tenares, Dominican Republic, mesmerized Royals fans with a fastball that averaged nearly 100 mph. He buckled opponents, compiling a 2.75 ERA in the years since his 2011 debut. And he allowed just four earned runs in 22 playoff appearances, ultimately winning a ring alongside teammates he called family.

“I was born and raised as a player here,” Herrera said.

“I’ve been playing with Duffy, Moose, Salvy, Hosmer since I was 18 years old. Then we came here together, and it made me feel better. After that, we went to the World Series. It was one of the best experiences ever.”

Not even a 2017 campaign in which he posted a 4.24 ERA and blew five saves in his first year as the Royals’ closer could darken his success in a Royals uniform. Especially not when this season he began to experience something of a career renaissance: Herrera was 1-1 with a 1.05 ERA and 14 saves in 16 chances across 27 appearances for the Royals. Among qualified relievers, Herrera entered Monday with the sixth-lowest ERA and the third-lowest walks-per-nine-innings rate (0.70).

In the final year of his contract, during which he is owed $7.94 million, Herrera had positioned himself perfectly to become a valuable asset on the trade market.

“We’d like to be holding onto our players longer, but where we are in the standings and what we’re faced with, how we’re playing _ if we can get the right deals, it’s important to move,” Royals general manager Dayton Moore said. “You certainly don’t want to disrupt chemistry in the clubhouse, but we’re all professionals. We have to make decisions on what’s best for the Kansas City Royals.”

In the days after Jon Jay was traded to the Diamondbacks, marking one of the first pre-deadline moves made by any team this season, Moore indicated the Royals would not make a trade unless it made sense for both sides. The words weren’t meant to sound hollow; they were meant to stifle the idea that the Royals would rip their major-league roster for parts without sound logic.

The Nationals provided enough in return for Herrera for the Royals to feel justified in that cause Monday. In Perkins and Gutierrez they received “elite-type defenders,” Moore said. Gutierrez, particularly, could be an asset at shortstop, where he showed advanced defensive capability before being moved to third base.

Both have demonstrated promise on offense. Perkins became a switch-hitter after being selected in the second round of the 2015 draft out of Verrado High School (Ariz.), and last year hit at all eight of his home runs from his nondominant left side. Gutierrez was batting .274 with six doubles, three triples, five homers and 36 runs scored in 58 games for Class AA Harrisburg this season, and has a 6-foot-3, 216-pound frame Moore said could still develop power.

In Morel, the Royals received a 17-year-old from the Dominican Republic who signed with the Nationals last summer out of Samana, the same province on the northern coast of the island where late Royals pitcher Yordano Ventura grew up.

Morel will join the Royals’ rookie league affiliate in Arizona this summer. Perkins, 21, was assigned to Class A Wilmington and Gutierrez, 23, to Class AA Northwest Arkansas.

With Herrera becoming a free agent after the season, the Royals didn’t have much leverage. Yet they received the Nationals’ 10th and 11th-ranked prospects, per MLB.com’s pipeline, and a young arm they scouted during the previous international signing period.

“I believe we found three really high-quality guys,” Moore said.