CINCINNATI -- On Saturday afternoon in Louisville, Reds left-handed pitching prospect Andrew Abbott saw that Triple-A teammate and outfielder T.J. Hopkins was getting his first big league promotion. Besides being happy for Hopkins, Abbott had one other thought.

“He’s my roommate in Louisville, so I was like, ‘I’ve got to pack his stuff up now,'" Abbott thought.

An hour later, Louisville manager Pat Kelly learned there was more news. Abbott would have to pack bags for himself, too. And instead of starting on Sunday for the Bats, he'll make his big league debut in a start vs. the Brewers on Monday. In a corresponding move, right-hander Kevin Herget was optioned to Triple-A Louisville, and right-hander Frank German was designated to make room on the 40-man roster.

• What to expect from Andrew Abbott in the big leagues

“It hasn’t set in yet, really," Abbott said. "Just a cool moment seeing all the guys that you saw in Spring Training and being in the same clubhouse. It’s a little bit bigger than Louisville, so it’s nice to space out and relax a little bit. It will hit me [Monday] but we’re ready for it. Just go out and get the job done.”

The Reds youth movement is continuing to sprout elite prospects reaching the big leagues in 2023. Abbott, 24, is ranked by MLB Pipeline as Cincinnati's No. 6 prospect and No. 95 overall in baseball. He will join shortstop Matt McLain (No. 5 in organization, No. 90 overall) and lefty starter Brandon Williamson (No. 10 in organization) as recent call-ups to the big leagues for their debuts. The Reds' No. 14 prospect, right-handed starter Levi Stoudt, was up for two brief stints earlier this season.

Over 10 starts this season for Double-A Chattanooga and Louisville, Abbott is 4-0 with a 2.50 ERA and 0.93 WHIP. In 54 innings, he has walked 17 while he's struck out an astounding 90 batters.

Abbott was Cincinnati's second-round pick in the 2021 Draft out of Virginia after he went undrafted in the abbreviated 2020 Draft. He worked as a reliever in his first three years of college before moving into the rotation his final year.

"[It was] just never giving up on myself because I didn’t get drafted in the COVID year and going back to school to try to prove to teams, 'You should’ve drafted me the year before.' It worked out as we can see," Abbott said.

Unlike Hunter Greene, Graham Ashcraft and Nick Lodolo, three starters in their sophomore seasons, Abbott is not a power pitcher. His fastball velocity sits mostly in the low 90s, but it has deception and cut that can frustrate hitters. His progress really accelerated in 2022 when he added a slider to the mix with his fastball, changeup and curveball.

The slider, taught to him by Chattanooga coaches Rob Wooten and Nate Irving and Minor League coordinator Bryan Conger, quickly became one of his better pitches.

"I didn’t think it would click that early and that soon," Abbott said. "But it’s gotten better over time just throwing and being repetitive with it. It’s been successful so far and hopefully it continues.”

Abbott was moved up from Chattanooga after three starts with a 1.15 ERA. He's made only seven starts at Triple-A, but the Reds felt he was ready.

"He's got a very mature approach even though he's not been here before," Reds manager David Bell said. "He pitched in college and just kind of handles himself like he belongs, in a good way. That always gives you more confidence in getting a guy to the Major Leagues, maybe a little bit quicker just because he hasn't pitched a lot in Triple-A, but he has a lot of experience pitching, which gives you confidence."

With Abbott starting Monday, the Reds are briefly going with a six-man rotation to accommodate Greene as he is dealing with right hip stiffness. His scheduled start for Tuesday was bumped back to next Sunday at St. Louis to avoid putting him on the injured list. Monday's originally scheduled starter, Luke Weaver, will face the Dodgers on Tuesday, and everybody else in the rotation was moved back a day.

Abbott was assigned uniform No. 41. One of the more famous players to previously wear the number was a lefty pitcher in the beloved Joe Nuxhall. It also belonged to Tom Seaver and World Series-winning manager Lou Piniella.

“Some names to follow up there," Abbott said.