Shohei Ohtani works in the bullpen Saturday ahead of his first start in the majors Sunday against Oakland. “He’s very coachable,” said his former pitching coach. “He does things before we even tell him to do that. There’s some intuition.” (Thearon W. Henderson/Getty Images)

Until now, the Shohei Ohtani story has followed a predictable trajectory. There was the relentless accumulation of speculation and news leaks ahead of his December signing with the Los Angeles Angels, and the breathless chronicling of his two-way talents in Japan, replete with tales of 103-mph fastballs and 500-foot homers. There was the wall-to-wall documentation of his first days of spring training, followed by the inevitable flow of criticism from anonymous scouts the moment he struggled.

We had already endured one full cycle of buildup and teardown — from how “the Babe Ruth of Japan” would revolutionize Major League Baseball to how he really ought to be in the minors — before Opening Day even arrived.

On Sunday, though, some time after the sun begins its westward drift toward the Pacific Ocean, Ohtani will climb a circular dirt mound at the center of a giant concrete bowl and do something the sport of baseball, as it is played on these shores, has not witnessed in almost 100 years. And from that moment on, the trajectory of the Ohtani story will no longer be so predictable, despite the cynicism of those jaded sorts who would tell you they already know how this is going to go.

Having already started on Opening Day three days earlier as the Angels’ designated hitter — smacking a sharp single on the first pitch he saw and going 1 for 5 — Ohtani, 23, will be the starting pitcher at Oakland-Alameda County Coliseum in the fourth game of the Angels’ season. The moment he throws his first pitch, he will become the first player since Boston’s “Bullet” Joe Bush and Brooklyn’s Clarence Mitchell in 1920 to start as both a non-pitcher and a pitcher in a team’s first 10 games of a season.

But since neither of those names are likely to ring a bell — Bush was a full-time pitcher of middling talent who made two starts in the outfield that season, and Mitchell was a part-timer at both disciplines — just go ahead and think of it like this: 99 years after Ruth essentially abandoned pitching to focus on hitting, a decision that worked out fairly well for him, Ohtani will become the first player since the Babe himself to make a go at doing both on more or less a full-time basis. (Willie Smith made 373 plate appearances, mostly as an outfielder, and 15 appearances as a pitcher, mostly as a reliever, for the Angels in 1964, and Brooks Kieschnick was a part-time pinch hitter and reliever for the Milwaukee Brewers in 2003-04.)

Ready for the moment

The sheer audacity of that effort, and the sheer amount of talent it requires, should not be lost amid the incessant focus on results that is certain to dominate the Ohtani story from this point forward.

“It’s something I’ve never seen, and something, really, no one alive has ever seen,” said Angels center fielder Mike Trout, forgetting that a hardy centenarian, theoretically, could have once watched Ruth play. “So I can’t wait for it. I give the guy a lot of credit just for trying it and I personally think he’s going to be great.”

If the enormity of the moment is threatening to overwhelm Ohtani — a 6-foot-4, 203-pound specimen who bats left-handed and throws right-handed — you wouldn’t know it from his face, his demeanor or his words. His workdays follow a carefully scripted schedule — he DH’ed Thursday, threw a bullpen and took batting practice (but didn’t play) on Friday — and Saturday was set aside for rest and for beginning the mental transition into pitcher mode ahead of Sunday’s starting assignment.

On Saturday morning, he floated through the visiting clubhouse saying “Good morning!” to teammates and media members — his English still poor but improving by the day — then sat at his locker, wearing team-issued workout clothes and a pair of pink-and-black shower shoes, chatting and laughing with his friend and interpreter, Ippei Mizuhara. After emerging onto the field some 90 minutes before Saturday’s game to stretch and run in the outfield, he stopped first at the stands between the Angels’ dugout and home plate to sign autographs.

“My first impression is, he looks like he’s having fun,” said Tomohiro “Johnny” Kuroki, Ohtani’s former pitching coach with the Nippon Ham Fighters, now a commentator for Tokyo’s J Sports TV and one of a pack of nearly 100 Japanese media members on hand to chronicle Ohtani’s debut this week. “ . . . If it’s an important game, like an opening game or a game we need to win, he has enormous power [of focus] on a game like that. There is no doubt he is a player with big dreams.”

Ohtani’s struggles this spring — which included a 27.00 ERA in two Cactus League appearances and .125/.222/.125 slash-line in 36 trips to the plate — begot a rash of stories, some of them quoting unnamed scouts, about how unprepared and even under-skilled he is for what he is trying to do.

It is worth remembering there wasn’t a team in the majors that didn’t want Ohtani this winter, particularly given the low bonus and minimum salary he would earn as an under-25 foreign player. Most American talent evaluators seem to think he will eventually hit himself out of a DH job but has a chance to become a dominant pitcher — but oddly, most Japanese observers take the opposite stance: that he is actually better at hitting than at pitching, and that the opposing American view simply reflects our obsession with velocity over craft.

“At this point, he’s a better hitter than pitcher,” Hideki Kuriyama, Ohtani’s manager with the Fighters, told American reporters last year. “He’s still not a complete pitcher yet. He hits very naturally. He throws the ball very hard, but he’s not a complete pitcher yet.”

Entering the unknown

While Ohtani’s mechanics and numbers are scrutinized obsessively, Ohtani the human being, perhaps because of the differences in culture and language, is still something of a mystery, at least here. He is exceedingly polite and earnest, looking each questioner in the eye and doing his best to accommodate the enormous media appetite for him — but he gives away little of himself, his inscrutability his most obvious personality trait.

He is also just 23, having lived a largely sheltered life. Born and raised in a small town in the northern prefecture of Iwate, he had only lived with his parents and in the Fighters’ dormitories before moving to the States this winter. He still does not have a driver’s license and lets his parents manage his finances.

Asked on Thursday whether his experience in MLB so far has confirmed or increased his expectations of how difficult the task will be, Ohtani said through his translator, “I think it’s still too early to say whether it’s harder or not. It’s going to be a long season, and throughout the season there’s probably parts where I will feel like, ‘Oh, this part was harder,’ or, ‘This part was not as hard.’ I just want to enjoy the season.”

“I don’t know if you get a [full] sense of how hard he’s worked to get acclimated to baseball in the United States,” Angels Manager Mike Scioscia said. “ . . . We’re going to see how this goes.”

In the short time he has been in the States, Ohtani has already undergone a fairly significant change in his batting mechanics, abandoning his high leg-kick and keeping his lead foot closer to the ground.

“He’s very coachable,” said Kuroki, the former pitching coach. “He works on his own. He does things before we even tell him to do that. There’s some intuition.”

In terms of quality of play, Japanese professional baseball may be a notch below that of MLB, but in terms of nickname coinage, they are the big leagues and we are Class A. In America, we have taken to calling Ohtani the “Babe Ruth of Japan” because we have no imagination and because everything, whenever possible, always goes back to the Babe.

In Japan, however, they call him “Nitoryu,” a reference to the two-sword fighting style developed by venerated 17th century warrior-philosopher Miyamoto Musashi.

There will be time later to judge results and to calculate the potential life span of Ohtani’s two-way dream — though if and when it eventually ends, it is just as likely to be the result of baseball’s institutional inflexibility as through some failure of the player himself.

But for now, let’s try to appreciate the talent, the effort and the dream, because American baseball has seen almost everything in a century and a half of history — including one Babe Ruth already — but until Ohtani takes the mound Sunday, it has never seen a Nitoryu.