MESA, Ariz. -- The group of Giants Minor Leaguers in the visitors’ dugout at Field 6 erupted in cheers as the ball jumped off the bat of Bryce Eldridge on Wednesday afternoon. Cubs lefty Shota Imanaga called for a new baseball and made some mental notes.

The towering home run that Imanaga yielded in the first inning to the 19-year-old Eldridge -- MLB Pipeline’s No. 4-ranked Giants prospect and the No. 96 prospect in baseball -- came via a slider that caught far too much plate. Imanaga has shown a knack for quick adjustments in his first MLB Spring Training and this start proved no different.

“My biggest takeaway from today’s outing,” Imanaga said via his interpreter, Edwin Stanberry, “was in the first inning I threw a slider that got hit for a home run. Making that adjustment, the quality of the slider was a lot better towards the end of the game.”

In fact, the next time Imanaga faced the 6-foot-7 Eldridge, the Cubs' lefty used a sharp slider that dove away from the young slugger’s bat. It was one among 13 strikeouts that Imanaga registered against the 22 High-A batters he faced in the appearance. It was a controlled environment in which the lefty could keep testing the feedback received this spring on his pitch arsenal.

While the Cubs ran out a line of relievers in a 3-1 loss to the A’s in a Cactus League game at Hohokam Stadium, Imanaga and lefty Jordan Wicks each logged 5 1/3 innings on the backfields at Chicago’s complex. Imanaga built up to 88 pitches in the start, which included one run allowed on five hits with two walks. The lefty erased one baserunner with a quick pickoff move to first base.

“He’s a veteran guy,” Cubs pitching coach Tommy Hottovy said recently. “It's fun to communicate, show him information and show him why we think things should work. And then for him to trust you in that moment and go do it in the game, and actually be able to execute what you want to do.”

One of the big adjustments the Cubs have been working on closely with Imanaga this spring has been the execution of his fastball. Hottovy noted that the team has set up an apparatus with strings to display the strike zone in bullpen sessions, during which Imanaga has concentrated on elevating his fastball.

In Japan, targeting the upper tier of the strike zone is less common, given the hitters’ tendency to lay off the pitch and the result often being deemed a ball. Pitchers in the Major Leagues attack the upper part of the zone more frequently, and the Cubs feel Imanaga’s fastball -- one with exceptional movement -- can be a real weapon in that area.

“We knew coming into it, it was a gift that he had. The elevated heater,” Cubs catcher Yan Gomes said. “Looking at it from his outings in Japan and how he was facing hitters, some of the communication was that he would rather dot something down and away than blow it by hitters. He mentioned a little bit of the MLB style of hitters and the Japan style of hitters. It's such an elite fastball. It's not necessarily, like, throw it up, as much as it's just using it at the top of the zone a little bit more.”

Hottovy said one thing the pitching group has done is show Imanaga the movement profile of effective pitches, compared to the ones that might feel good or look good to the lefty in the moment. At times, when the fastball has felt good to Imanaga, it has had more run (away from a right-handed hitter). The goal is to better feature the cut-ride action that can make his heater elite.

Imanaga has been focusing on taking that feedback and learning how to trust the movement, as opposed to trying to force movement.

“In Japan, I had fabulous coaches and fabulous advice from them,” Imanaga said, “but over here, through coach Tommy and other coaches, I can watch videos of myself and then get a deeper understanding of the pitcher I am.”

In his most recent Cactus League start this past Thursday, Imanaga faced the A’s and struck out nine batters with no walks in 4 1/3 innings. During that start, the left-hander focused on attacking the top of the zone with his heater and then -- when Oakland’s hitters began to stop swinging at it -- he generated more whiffs with his splitter.

It was an overpowering performance by the pitcher the Cubs invested in with a four-year, $53 million deal over the offseason.

“If you watched Shota pitch the last time,” Cubs manager Craig Counsell said, “there's really not much to tinker with there. There's no reason to tinker with any of that. There's no reason. You don't have to do anything different. You don't have to be better. That'll work.”