OAKLAND -- Mason Miller pitched his way onto the big league radar with an impressive showing in Spring Training. After dominating through the first couple of weeks of the Minor League season, his electric arm became too much for the A’s to ignore.

Miller, Oakland’s No. 3 prospect per MLB Pipeline, was officially added to the active roster in time to start Wednesday’s series finale against the Cubs. The third-round selection by the A’s in the 2021 MLB Draft will reach the Majors after just 11 games of Minor League experience.

“I’d like to think that I thought I was good enough to get here sooner than everybody expected, but I think even I’m a little surprised by how fast it was,” Miller said. “I’m going to take the opportunity and run with it.”

Injuries have limited Miller’s opportunity to pitch in the Minors. But the A’s had seen enough in their evaluation of the 6-foot-5 right-hander to make it clear that a big league promotion was possible at some point this season. Making his 2023 Triple-A debut on Friday night, Miller’s dazzling performance of 11 strikeouts and no walks over five hitless innings sealed the deal.

“I watched every pitch Mason threw in Las Vegas the other night, and if that’s not forcing your way here, I don’t know what is,” A’s general manager David Forst said. “He is inexperienced and he is young. He will have ups and downs. But he is incredibly talented, and a number of factors made it so that he is the right guy to be here tomorrow and start the game.”

Among those factors is a struggling A’s starting rotation that entered Tuesday with a Major League-worst 9.39 ERA as a staff and tied for third-most walks (40). Including his 19 strikeouts and no walks in 8 2/3 innings this season, Miller holds a 2.83 ERA with 53 strikeouts and six walks in 28 2/3 innings over his Minor League career.

While the track record is not extensive, Miller has shown the ability to consistently throw strikes throughout his professional career.

“We need anything we can [get] right now to help stabilize the staff,” Forst said. “We’ve had too many nights where the bullpen has been in the game in the third and fourth inning. … That has had a snowball effect on the rest of the group.”

The fastball is a clear standout pitch in Miller’s arsenal. During that Friday outing for Las Vegas, he frequently hit triple digits, with 23 of his 65 pitches registering 100+ mph. Of those 23, only eight went for balls, showing that he’s a flamethrower that also comes with supreme command.

Miller has also integrated a cutter into his repertoire, which made headlines during a Cactus League outing this spring when he left Mariners outfielder Sam Haggerty in disbelief after falling to one knee on an off-balance swing and miss. Miller threw that cutter 12 times on Friday night and maxed out at 98 mph.

Miller brings excitement as a potential ace of the future, and the plan is for him to remain in Oakland’s starting rotation beyond his Major League debut on Wednesday.

“I’m really excited,” Miller said. “Pitching on the big stage has obviously been a dream as long as I can remember. To have that sitting in front of me, I’m honestly anxious and ready to get going.”

As for the rest of the rotation, manager Mark Kotsay said the situation remains fluid. James Kaprielian, who was originally scheduled to make Wednesday’s start, pitched out of the bullpen on Tuesday against the Cubs, throwing one scoreless inning.