MESA, Ariz. >> As Oakland’s starting rotation takes shape this spring, a number of young, largely-unproven pitchers are vying for an opportunity to log valuable major-league innings this season, as well as a chance to establish themselves early in their careers.

Kyle Muller is no exception.

The 25-year-old left-hander has drawn a lot of praise since the beginning of spring training and is expected to compete for a spot in the A’s rotation, a group he hopes to be a fundamental piece of after spending parts of the last two seasons in Atlanta. The former No. 1 overall pitching prospect in the Braves’ farm system has had his fair share of struggles — but mostly success — through the first six years of his professional career. But a new opportunity in Oakland could be just what he needs to burst onto the major-league scene.

“All I have wanted this entire time is an opportunity to get comfortable and pitch every five days in the major leagues and see how I stack up against the best in the world,” Muller said. “I feel like that chance is strong here and I just have to go prove myself.” Muller was acquired over the offseason in the Sean Murphy trade, joining veteran catcher Manny Piña, as well as fellow top prospects Esteury Ruiz, Freddy Tarnok and Royber Salinas in Oakland. He rejoins his close friend, Shea Langeliers, whom Muller spent a lot of time with in the Braves’ system.

Despite having to make the unexpected transition over the winter, Muller said he instantly embraced the opportunity for a fresh start with the A’s.

“I had pretty much grown up there,” Muller said of his time with Atlanta. “I was there since I was 18 to 25. Having everything kind of flip like that in a minute and a half phone call, it was kind of wild. But immediately after I got the phone call I was so excited. I texted Shea immediately and I called my parents and told them.”

The 6-foot-7 lefty logged 49 big-league innings with the Braves over the last two seasons, though his stints in Atlanta were brief. Muller spent most of his time in Triple-A Gwinnett, where he was arguably at his best since he was drafted in the second round of the 2016 MLB Draft. He posted a 3.39 earned run average across 79.2 innings in 2021, making 17 starts. He followed that with a 3.41 ERA in 134.2 innings last season. Muller collected 252 strikeouts between those two seasons in Triple A.

Last season in particular was a breakthrough for Muller.

“I was probably the most complete person, player, and pitcher that I’ve ever been,” he said. “I really figured out what clicks for me and where I need to be in terms of pitch usage, tunneling and mentality on the mound, knowing where my mechanics are where they need to be. Every year before that I’ve changed my delivery, but I got to a consistent point in my delivery where I can just repeat it and focus on repeating it.”

A’s manager Mark Kotsay said Muller will have an opportunity to prove himself against big league hitters throughout camp as he battles for a spot in the rotation, but the towering left-hander has to compete if he is to claim one of the five spots.

“He had success at the Triple A level for a long period of time,” Kotsay said. “Now it’s time for him to go out and really capture this opportunity that he has to make this rotation and be an impact starter for us.”

Joining the A’s likely helps Muller, given that the roster is teeming with high-caliber talent looking to make an every day impact at the big league level. He cited that youthful, blue-collar dynamic as an enjoyable aspect of his experience with the A’s thus far after struggling to establish himself among an All-Star cast in Atlanta.

“I was always trying to make sure I wasn’t in other people’s way. But here everybody is in the same boat, so I immediately felt the comfort of being able to just be myself and do my own thing and interact with people and not have to worry about pissing off a veteran. All the older veteran guys here have been super cool, very approachable. And they were like that in Atlanta as well, it was just kind of intimidating.”

Fujinami to debut against old rival Ohtani >> On Thursday, Kotsay revealed rookie Japanese right-handed pitcher Shintaro Fujinami will make his first appearance of the spring on Tuesday against the Angels.

But his highly anticipated debut is perhaps even more significant after the Angels announced earlier in the week that Shohei Ohtani will also pitch Tuesday.

Their duel was not initially planned, according to Kotsay.

“That’s Fuji’s day, it just happens to coincide with the day that Ohtani is pitching,” Kotsay said. “I’m sure there will be a lot of excitement about these two. I know it’s been a long time since they have been on the same field together. Outside of it being spring training it should be exciting.”

Fujinami, who signed a one-year contract with the A’s in January, was a first-round pick in the 2012 NPB Draft along with Ohtani, who he faced in high school at the National High School Baseball Championship of Japan.

The two were often compared as prospects during their high school years, but took starkly different routes to MLB.

Following his first live batting practice session of A’s camp, Fujinami expressed his excitement in not only getting to face his Japanese compatriot in his debut, but to get on the mound in general.

“Obviously it’s going to be my first game in spring, I might get nervous a little bit, but I look forward to it,” Fujinami said through Japanese interpreter Issei Yamada.

“I think it’s a rare matchup. I’m pretty sure Japanese fans are looking forward to it. I look forward to pitching against (Ohtani) too.”

Young newcomers look to prove themselves >> The A’s will begin Cactus League play on Saturday against the Arizona Diamondbacks, a date that many of the A’s newcomers in particular are excited for.

It marks a lot more the start of a new season, but an entirely new chance with their new ballclub. The A’s have plenty of players who fit that mold this spring, which perhaps makes it easier for those who are still unfamiliar with their new surroundings to get acclimated.

“It’s good to have a bunch of young guys around who you can relate to and bond with a little bit and spend some time with,” said outfielder JJ Bleday, who was acquired in a trade with the Marlins just over two weeks ago. “Kind of get yourself away from baseball and have that camaraderie aspect to it.”

Many of those newcomers, like Bleday, haven’t even logged a full year of big league service time to this point in their careers, and yet are in a position to compete for starting roles this spring.