OAKLAND -- There is perhaps no pressure-free way to make a Major League debut, but Ky Bush drew a particularly tough assignment with a rather undesirable piece of AL history hanging in the balance.

The White Sox fell to the A's, 5-1, in Monday night's series opener at the Coliseum. Their 21st loss in a row tied the 1988 Orioles for the longest losing streak in AL history, and only the 1961 Phillies (23) have lost more consecutive games.

Bush, Chicago's No. 17 prospect, showed promise in his first big league start but was charged with the loss after giving up three runs in four innings. He struggled with his command, issuing five walks and throwing just 45 of his 84 pitches for strikes.

"Obviously, not all the stuff was there," said Bush, who walked the bases loaded in the first. "I was spraying it a little bit. I mean, after that first inning, [I] settled in and just figured, 'Just go right at them and compete, really. Just give 'em your best stuff.'"

The White Sox left-hander didn't allow a hit until JJ Bleday doubled with one out in the fourth. A walk and a hit-by-pitch loaded the bases again, and this time, the A's were able to do a little more damage. Max Schuemann drove in two runs on a single -- the second and final hit Bush allowed.

“I’m assuming nerves played something into [the walks]," A's manager Mark Kotsay said. "The game plan was to get him in the zone. I thought, for the first couple innings, our guys were having a tough time maybe recognizing the breaking ball. Maybe it was a little bit of an extension to the fastball."

The debut ended better, though, as Bush rang up his second-to-last batter and induced a flyout to right to end his outing.

"Ky got the first one out of the way," White Sox manager Pedro Grifol said. "I thought, at times, he threw the ball really well, but at the end of the day, we've got to eliminate some of those free passes."

There was a vacancy in the White Sox rotation after Drew Thorpe went on the 15-day IL with a right forearm flexor strain on Friday. Bush is Chicago's fourth rookie starter to debut this season, joining Thorpe, Jonathan Cannon and Nick Nastrini.

Bush joined the White Sox organization alongside catching prospect Edgar Quero (No. 3 White Sox Prospect) ahead of the 2023 Deadline in the deal that sent Lucas Giolito and Reynaldo López to the Angels. Bush was Los Angeles' second-round pick in the '21 Draft out of St. Mary's College, about a half-hour drive from the Coliseum.

The 24-year-old Utah native attended big league Spring Training as a non-roster invitee, where he caught Grifol's attention with his stuff and composure.

"I wasn't anticipating that he'd be here so quickly, though it doesn't surprise me at all just because of the talent," Grifol said. "This is opportunity. This is preparation meeting opportunity."

Limited by injuries early in 2023, Bush took a step forward in his first full season in the White Sox organization. He began the year with Double-A Birmingham and went 5-3 with a 2.12 ERA across 14 starts, striking out 78 against 32 walks. He was promoted to Charlotte on July 6 and saw mixed results in his first taste of Triple-A, posting a 6.16 ERA in four appearances (two starts).

"It's really cool," said catcher Chuckie Robinson, who caught one of Bush's outings with the Knights and worked with him during Spring Training. "He has good stuff, he's a good guy. … It's exciting for him and for the team."

With how this White Sox season has played out, these last two months are more about playing for the future than the results. Chicago's top prospects, such as Bush, are getting opportunities to prove they can contribute in 2025 and beyond.

That doesn't erase the unenviable history that the team finds itself making. It's all but impossible to ignore as the streak drags on.

"It's 21 in a row. It sucks," Grifol said. "It's not fun, it's painful, it hurts, you name it. However you want to describe it. Like I said, it's not for lack of effort. Nobody wants to come out here and lose. We've just got to put a good game together and put this behind us."