MESA, Ariz. -- With the Giants nursing a one-run lead in the eighth inning Sunday, manager Gabe Kapler called right-handed prospect Luis Madero into the game. As Madero faced the A's, Sean Hjelle started warming up in the bullpen. Kapler saw Hjelle getting loose and called down to make sure he knew he was getting the ninth, not part of the eighth.

"He was the one pitcher today who got loose before we told him to get loose," Kapler said, smiling.

The 22-year-old, picked one round after Joey Bart in the 2018 draft, was excited to make his spring debut for the big league club and hid any butterflies. Hjelle is known for standing 6-foot-11 and having uncanny command and body control for a pitcher that size. But he came out throwing 95 mph and bumped 96 in a perfect inning, closing out a 5-3 win that clinched Kapler's first handshake line in orange and black.

"As much as we're excited by his stuff, we're also excited by him pounding the strike zone," Kapler said. "That's certainly encouraging to see him come out there in this situation, certainly a nerve-wracking situation, and fill up the zone with his fastball."

Hjelle, the organization's top pitching prospect, reached Double-A last season and could debut this year. It was one inning and he was amped up, but the ceiling certainly will get a bit higher if he's sitting 95 in the future instead of the low 90s. The Giants always have felt there was more velocity in that massive frame.

Here are four more observations from the first 18 innings of the Kapler Era ...

--- There was a new whiteboard up in the clubhouse this morning with a bunch of circles and a spot for each game this spring. A photo of a beaming Austin Slater was glued inside the first circle, making him the "baserunning BOSS" from Saturday's game. The Giants have put a heavy emphasis on leads and turns this spring and the new staff has identified that as one area they can gain an edge. One player will be recognized after every game.

We'll see if it works. This isn't a roster with much speed, but guys were aggressive Sunday and it led to a couple runs. Kapler credited first base coach Antoan Richardson for his work thus far.

"We really want them to push the envelope," he said.

--- Kapler has been hesitant to offer many public criticisms, but when asked about Derek Rodriguez the other day, he immediately mentioned that the staff needed to see more velocity from the starter/reliever heading into his third season. Rodriguez's average fastball dropped from 91.6 to 90.7 year over year. Rodriguez pumped a few 93s in his first inning of the spring and generally sat at 92, a positive sign this early.

"The first day of the spring, I'm happy about that," he said.

Rodriguez said he took just two weeks off in the offseason -- to plan for his wedding -- and then got to work on mechanical changes. He made three Winter League starts and was encouraged by how he felt there.

--- When Max Muncy came up early in Saturday's game, Evan Longoria shifted over to the right side but he didn't stand where he would last year. Longoria played kind of behind the first baseman, with Donovan Solano playing up the middle behind the bag. Last year the Giants had Longoria shift over between the second baseman and shortstop; this year he's between the second baseman and first baseman. It makes a lot more sense this way, allowing the actual second baseman to stay close to the bag where he might have to make a turn.

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--- Some early standouts, aside from Mauricio Dubon and Joey Bart, who homered Saturday: Matt Carasiti, a non-roster invite who struck out the side in his lone inning and got A.J. Pollock and Kiké Hernandez ... Abiatal Avelino, who hit a laser onto the berm in left on Sunday ... Kean Wong, who had two hits and showed his speed ... Finally, Rob Brantly, who has brought constant energy to camp and capped Sunday's game by yelling "Never in doubt!" as the Giants celebrated a spring win. Every team needs a quirky backup catcher, right?