There are myriad reasons the Orioles are excited for the return of Minor League Baseball, which resumed nationwide Tuesday night for the first time since the pandemic. And one of those reasons is the big left-hander set to take the ball every fifth day at Double-A Bowie.

Making his first regular-season start in more than 20 months, No. 4 prospect DL Hall showcased his immense promise in his season debut at Double-A Bowie on Tuesday. Striking out 10 over 4 1/3 scoreless innings, Hall dazzled dueling Pirates No. 20 prospect Roansy Contreras for much of the Baysox 2-1 win in the opener vs. Altoona.

Catcher Adley Rutschman (No. 1) went 0-for-5 with three strikeouts.

The O’s first-round Draft pick (No. 21 overall) out of the Georgia high school ranks in 2017, Hall showed dominant stuff across Class A and Class A Advanced during his first two full seasons of pro ball, and pitched a scoreless inning in the 2019 Futures Game. His fastball is playing near triple-digits now according to several reports, with a plus changeup and two distinct breaking balls. His main issue had been command (5.1 career walks per nine), but it wasn’t Tuesday: Hall walked two of the 15 hitters he faced.

At Bowie, Hall headlines an exciting rotation eight starters deep (No. 14 righty Kyle Bradish, No. 18 lefty Kevin Smith and Cody Sedlock among them), which the Orioles will manage creatively as a way to limit the innings of each pitcher coming off the long layoff.

Club officials have not disclosed exact figures for these benchmarks; in truth, they vary individually based on age, experience and injury history. For reference, Hall threw 94 1/3 innings at Delmarva in 2018, and 80 2/3 at Frederick in 2019 before a lat injury ended his season. He was lifted after 74 pitches Monday, despite allowing only three balls in play.

“Every single pitcher we’re going to be watching carefully and monitoring,” Orioles player development director Matt Blood said. “This is a little bit of an unprecedented situation. And the roster sizes are larger, and we will have large numbers of pitchers on each roster. So we will be monitoring it. But also we want these guys to get their work in. So it's a little bit of a double-edged sword.”

Elsewhere in the Minors

• Speaking on a Zoom call Tuesday afternoon, Blood said Heston Kjerstad would be transferred from the club’s alternate training site to extended spring training in Florida next week. From there, the No. 2 overall pick in the 2020 Draft will begin a progression back to baseball activity as he continues to recover from myocarditis. There is currently no timetable for Kjerstad’s professional debut.

“It’ll be a slow build-up process for him,” Blood said. “No need to rush him as he gets back to full health and fully baseball condition.”

• No. 5 shortstop Gunnar Henderson didn’t waste time in his debut at Low-A Delmarva, homering in his first at-bat Tuesday against the Salem Red Sox. The O’s second-round pick in 2019 (No. 42 overall), Henderson turned as many heads as any other prospect at the team’s alternate site and instructional league in 2020, showing well at the plate and at various positions against older competition. The 19-year-old played 29 games in the Gulf Coast League after being drafted in 2019.

Worth noting

Before sending them off to affiliate ball, the Orioles had their entire group of Minor Leaguers at extended spring training vaccinated for COVID-19, according to Blood. They consider it progress toward their ultimate goal of vaccinating the entire organization; the O’s have promoted vaccinations heavily and are working toward reaching the 85 percent vaccination threshold recommended by MLB at the big league level.

From the trainer’s room

Two of the Orioles Top 30 prospects open the season nursing minor injuries, but neither should be sidelined for long. No. 8 right-hander Mike Baumann remains at extended spring training nursing what Blood called right arm “discomfort,” though Blood said Baumann should be cleared to pitch at Triple-A Norfolk by the end of the month. Baumann was slowed last summer by a right forearm strain that did not require surgery, and eased into action this spring.

No. 10 left-hander Keegan Akin (left index finger laceration) should be back on the mound even sooner. Blood said Akin was scheduled to throw a side session Wednesday and start Friday for Norfolk, his first game action since slicing himself with a kitchen knife last month. Akin went 1-2 with 4.56 ERA down the stretch in the Majors in 2020, but did not make the big club out of camp this spring.

At the big league level, outfielder DJ Stewart returned to the O’s starting lineup Tuesday after a one-day absence due to back stiffness. Stewart batted fifth and started in right field for the middle game of Baltimore’s three-game series at Seattle.