SARASOTA, Fla. -- Two summers ago, Michael Baumann, Zac Lowther, Dean Kremer, Alexander Wells and Bruce Zimmermann comprised one of the top rotations in pro baseball. This was at Double-A Bowie in 2019, the first year of the Orioles’ new data-driven approach to player development that yielded widespread improvement throughout their system. Up and down their Minor League ladder, strikeouts skyrocketed. Walk rates plummeted. Bowie’s rotation was the hallmark for that growth, with the Baysox reaching the Eastern League finals behind its staff, which ranked No. 1 in ERA and WHIP.

In achieving that cumulative success, each rotation member performed excellently individually: Baumann pitched to a 2.31 ERA in 13 outings, tossing a nine-inning no-hitter in his sixth start; Lowther went 13-7 with 2.55 ERA in 26 starts, suppressing home runs at an elite rate; Kremer breezed to a 2.98 ERA in 15 starts, earning a late-season promotion to Triple-A Norfolk; Wells was a soft-contact machine, posting a 2.95 ERA and issuing just 24 walks in 137 1/3 innings; Zimmermann enjoyed a career year, with a 2.58 ERA and as many strikeouts as innings pitched.

“We’ve had great times together,” Baumann said recently. “It's been awesome, coming up with Zach and Dean, and these guys.”

Now they’re all knocking on the Major League door, more or less simultaneously. The entire group, which includes four of the Orioles’ top 20 prospects per MLB Pipeline, is in big league camp this spring with an eye toward reaching Baltimore at various points in 2021. Together they comprise the first wave of pitching prospects that have helped buoy the O’s now highly touted system and have spurred optimism for an organization that’s historically struggled to develop high-quality arms.

“It's like having the crew back together again,” Zimmermann said. “Having those guys in camp has been a lot of fun. It brings back the competitive nature that we had in 2019 when we had such a great season.”

If not for the pandemic, they might all be in the Majors already. By the end of 2019, Kremer and Zimmermann had earned promotions to Triple-A, with the expectation Baumann, Lowther and Wells would soon join them there. But then ‘20 happened. Baumann and Lowther were instead limited to the O’s alternate site last summer, then Lowther participated in instructional league camp. (Baumann was rehabbing a right elbow strain at the time and is being eased back into action this spring.) Wells returned home to Australia and never left. Kremer and Zimmermann reached the big leagues, debuting less than two weeks apart in September.

Now, Kremer is getting every opportunity to hold onto a rotation spot, and Zimmermann is turning heads as he battles for a swingman job. Baumann and Lowther have mostly been limited to work on the back fields early in camp, and Wells is yet to pitch due to an oblique strain. The overwhelming likelihood is of Baumann, Lowther, Wells -- none of whom have pitched at Triple-A -- beginning the season at the O’s alternate site and spending at least some time afterward at Norfolk. But all are on the 40-man roster, hinting at imminent debuts.

Asked how close he feels to being a Major League pitcher, Lowther said, “I feel like I’m there. The only thing stopping me right now is not being on the roster.”

Said Baumann: “I just want to prove that I belong here. I know that I can and can go out and compete. But I also want to focus on what I need to work on to get ready for the season.”

The calculus is a little different for Zimmermann, the Ellicott City native and lifelong Orioles fan who rose steadily through the Braves and O’s systems despite never being considered a top prospect. He’s making the most of his opportunity this spring, striking out six across five scoreless Grapefruit League innings.

“All my springs so far have always been coming in ready to go because I’m trying to make the team, so I really don’t really play to the paradigm of easing into where I’m supposed to be at,” Zimmermann said. “I kind of come in hoping my stuff is pretty close to where I need it to be.”

To a man, they’ve all seen what kind of pitcher each can be when their stuff is playing best in real time. They each fit different molds. Baumann is a power righty with frontline build, a fastball that flirts with triple digits and a wipeout slider. Lowther is the highest Draft pick of the bunch, a second-round southpaw whose high-spin heater plays up due to deception. Kremer was acquired in the Manny Machado trade and features one of the best curveballs in the O’s system. Wells is a control artist whose results have outshone his stuff at every level, and Zimmermann is a four-pitch lefty who profiles both in the rotation and in relief.

By season’s end, it’s not difficult to envision all making starts in what is a clouded O’s rotation picture behind John Means, with Kremer and rookie Keegan Akin -- another Top 15 prospect -- likely to crack the Opening Day rotation along with Félix Hernández and either Matt Harvey or Wade LeBlanc. The others are seen as better long-term solutions than any of those reclamation project veterans, as well as important in the short-term in a year when depth will prove paramount.

For the Orioles, the premier challenge of 2021 will be balancing their development with workload restrictions due to the pandemic.

“It’s just so unprecedented. There is no playbook to this. I think you’ll see different teams and pitchers handle it differently,” O’s general manager and executive vice president Mike Elias said. “While we continue to talk about this from all angles, none of us have the exact formula for what’s best for these guys mapped out. There are so many case-by-case variables. All I can say is we’ll do the best we possibly can to navigate it with the players’ health first and foremost, and then the organizational goals and needs of the Orioles as a secondary factor.”

In any event, the Orioles believe the history these pitchers share can’t do anything but serve them well.

“I think guys pushing each other through the Minor Leagues, competing together and against each other and winning, I think it is an important part of development,” manager Brandon Hyde said. “It’s not the end all, in terms of what kind of player a guy will be when he gets to the big leagues. But I think it’s very, very helpful from an organization standpoint. Playing meaningful games in the Minor Leagues, I think there is definite benefit to that. Guys that have played together and done that, compete against each other as well as other clubs, I think there is an advantage there.”