CHICAGO -- As long as Spring Training has existed, there have been pitchers reporting to camp intent on working on a changeup. It is as much a tradition in baseball as Opening Day bunting adorning ballparks and the seventh-inning stretch.

This spring, Cubs lefty Justin Steele was the team's notable name fine-tuning an offspeed offering, and it very well could develop into a weapon for the starter. In the meantime, Steele has proved he can do just fine leaning mostly on a perplexing two-pitch combo.

"I know a lot was talked about the changeup," Cubs manager David Ross said. "But I think at the end of spring you could really see him just getting back to his bread and butter."

In a 3-1 loss to the Brewers on Saturday, Steele did his part with six scoreless innings that resembled his dominant close to a breakout 2022 campaign. The lefty relied mostly on his four-seam fastball and slider mix, sprinkling in a handful of other pitches to keep batters honest.

Before Steele took the mound against Milwaukee, Ross opined pregame that the pitcher could take an important step forward this summer by focusing on his strengths. Against the Brewers, it looked very much as though Steele heeded his manager's advice.

"That's kind of always been my thing," Steele said, "is throwing a lot of fastballs and a lot of breaking pitches. And yeah, as I mature and get older, I want to implement more pitches into my repertoire and just keep growing."

The 27-year-old Steele noted that he used mostly a fastball and curveball as he climbed up the Cubs' Minor League ladder. These days, the slider is his primary breaking pitch, though he has learned how to manipulate that pitch in a variety of ways based on situations.

Steele has learned to wield a slider that features more lateral movement -- almost to the point of slipping into the sweeper category -- to avoid the bats of lefties. He can also tighten it up some to target the strike zone to either edge.

Beyond that, Steele still has a curveball that he mixes in on occasion, along with a sinker and that evolving changeup. The lefty's four-seamer is another pitch he can use in different ways, giving it some late cut or late ride to move off the barrel.

"It's awesome," Cubs catcher Tucker Barnhart said. "It makes it extremely difficult on a hitter. It's a unique mix."

Barnhart said the characteristics of Steele's main pitches make it possible for him to attack right-handed hitters inside. When things are working properly, the catcher said hitters, "just smother it and hit a bunch of ground balls." Steele created eight outs on the ground on Saturday.

The Brewers were also whiffing at a steady clip against Steele, whose 14 swinging strikes were tied for his third-highest total in a single outing. He ended the day with eight strikeouts, while getting seven swinging strikes with the slider and another six with the four-seamer.

"You have to respect that fastball down and in, having caught a guy like that, to righties," Ross said. "And he's so tough on lefties with the angle. There's just some real, real deception there. And I think that late movement really helps him out."

The "guy" Ross referenced was former Cubs ace Jon Lester, who played a small role in Steele's development last year. There was a point in the season when Lester chatted with Steele about being more assertive on the inner third of the zone against right-handed batters.

After that conversation, Steele turned in a 2.05 ERA over 14 starts, lowering his season ERA to 3.18 from 5.40 in that span. It was the kind of finish that helped Steele head into the offseason and this past spring with a rotation job secured for this year.

Ross said the next step in Steele's development is continuing to get better at reading batters' swings with his catcher and making those in-game adjustments. That is when those third, fourth and fifth pitches gain value -- when the pitcher fully understands "why" it is the right time to use them.

"He threw a phenomenal game," Ross said of Steele's season debut. "That's as good as we've seen him."