PHOENIX -- Out of the corner of his eye, catcher Jeferson Quero saw White Sox second baseman Danny Mendick make a run for second on a steal attempt.

Without hesitation, Quero received the pitch from starter Aaron Ashby and threw to shortstop Yonny Hernández, who was getting in position.

They connected, and Quero threw out his fifth player in just seven games during Thursday's win.

Fans watched in amazement, and Brewers manager Pat Murphy smiled.

“He's got good hands -- meaning he's got quick enough hands and good enough hand-eye coordination that makes it just a work of art when you see him catch a ball,” Murphy said the day before Quero's latest feat. "His release, his throwing arm … exceptional.”

The 21-year-old again showed his dominance on defense, which helped him win the 2023 Rawlings Minor League Gold Glove.

"That kid is -- I mean, that's the gem of our organization right now," Murphy said. "You've got the starting catcher [William Contreras], and you've got this kid coming, who is really, really good."

When the game ended, Quero got on a bus to Las Vegas, where the Brewers will face the Athletics in two split-squad games on Friday evening and Saturday.

The potential that bullpen coach Charlie Greene has seen in Quero -- ranked by MLB Pipeline as the Brewers' No. 3 prospect and No. 35 overall -- was on display for everyone.

“I think I first saw him when he was 15, so he’s come a long way,” Greene said. “He’s a talented kid, we saw that from day one, and he’s developed.”

Quero’s ability to play defense did not come overnight. Over time, he had to learn to become more controlled and not let aggressiveness get the better of him.

Quero underwent shoulder surgery in the 2021 season while with the Brewers Blue in the Rookie-level Arizona Complex League. He also sustained a concussion and suffered hamstring issues, limiting him in '23.

His shoulder injury taught Quero that control and aggressiveness can go together.

“I now know I don’t have to overdo it to play my best,” he said in an interview in Spanish.

Quero spent 2023 with Double-A Biloxi, throwing out 27 would-be base stealers. In 336 at-bats, he recorded 16 homers, 12 doubles, and 49 RBIs.

In his second Spring Training with the big league club, Quero aims to become a better all-around catcher.

“That’s how we envision Jeferson,” Greene said. “Obviously, he’s a defensive standout, but we think he can be an offensive standout as well.”

Luckily for Quero, the Brewers have the 2023 Silver Slugger winner Contreras and veteran catcher Gary Sánchez, with whom he can work, train and learn from throughout the remainder of the spring.

Contreras said he tries to advise Quero on areas to improve, and Quero is receptive to the guidance -- a tweak here, a suggestion there.

“We’re always communicating and they’ve helped me a lot on small, but important things,” Quero said.

Quero even takes it upon himself to observe what his teammates do and implements what he observes in his routine.

“The expectations are higher this year compared to last year,” he said. “Now we’re working a little on my blocking numbers to set everything together and so everything turns out well.”

Hoskins hits a grand slam

Rhys Hoskins hit a grand slam for his second spring homer in the Brewers' 7-4 victory over the A's on Friday afternoon at American Family Fields. Along with the slam, he hit a double, going 2-for-3 on the day with five RBIs.

"I had made a comment in my at-bat before of just trying to back the ball up," Hoskins said. "A hard-hit ball to the opposite field is usually a good sign that you're doing that. Stick with the process and hopefully keep having good at-bats."

Prospect Gasser pitches well

The Brewers' No. 6 prospect, Robert Gasser, threw three scoreless innings in Friday's victory, striking out three batters and allowing two hits.