LOS ANGELES  — Only a week has passed since the Los Angeles Dodgers abruptly fired Ippei Mizuhara, the interpreter and constant companion of their new $700 million slugger, Shohei Ohtani.

But the biggest story of baseball's spring is still murky — and shocking — as the regular season begins in earnest Thursday.

The scandal encompasses gambling, alleged theft, extensive deceit and the breakup of an enduring partnership between the majors' biggest star and his right-hand man. Investigations are underway by the IRS and Major League Baseball, and Ohtani publicly laid out a version of events Monday that placed the responsibility entirely on Mizuhara.

Here are the basics as Ohtani and the Dodgers prepare for their home opener against St. Louis on Thursday:

Ohtani claims his close friend repeatedly took money from his accounts to fund his illegal sports gambling habit. Ohtani also says he was completely unaware of the “massive theft,” as his lawyers termed it, until Mizuhara confessed to him and the Dodgers last week in South Korea, where the team opened its regular season against the San Diego Padres.

Mizuhara has given more than one version of his path to this trouble, which was catalyzed by the IRS' investigation of Mathew Bowyer, an alleged illegal bookmaker. Mizuhara has consistently said he has a gambling addiction, and he abused his close friendship with the Dodgers superstar to feed it.

That's the biggest question to be answered in Major League Baseball's investigation, and the two-time AL MVP emphatically says he has never gambled on sports or asked anybody to bet on sports for him.

Further, Ohtani said Monday he has never knowingly paid a bookie to cover somebody else's bets. Mizuhara also said Ohtani does not bet, and Bowyer’s attorney said the same.

Mizuhara told ESPN on March 19 that Ohtani paid his gambling debts at the interpreter’s request, saying the bets were on international soccer, the NBA, the NFL and college football. If that were true, Ohtani could face trouble even if he didn't make the bets himself — but ESPN said Mizuhara dramatically changed his story the following day, claiming Ohtani had no knowledge of the gambling debts and had not transferred any money to bookmakers.

MLB rules prohibit players and team employees from wagering — even legally — on baseball. They also ban betting on other sports with illegal or offshore bookmakers.

Ohtani has played in every Dodgers game since the story broke, and he is expected to be their designated hitter in most regular-season games this season while baseball's investigation continues.

Ohtani says his legal team has alerted authorities to the theft by Mizuhara, although his team has repeatedly declined to say which authorities have been told, according to ESPN.

Ohtani's new interpreter is Will Ireton, a longtime Dodgers employee and fluent Japanese speaker who has filled several jobs with the team in everything from game preparation and analytics to recruiting free-agent pitches. But Ireton won't be Ohtani's constant companion, and manager Dave Roberts said Tuesday he's optimistic that Ohtani will become closer to his teammates without the “buffer” provided for years by Mizuhara.

MLB’s investigation of Ohtani’s role in the events could last weeks or months, and it’s unlikely to be publicized until it’s complete. No one outside of Ohtani’s inner circle knows what it will find or how serious any repercussions could be, and nobody outside the circle is making informed speculation about the process.

One major question looms: How did Mizuhara have enough access to Ohtani's bank accounts to get the alleged millions without Ohtani knowing? Is the slugger overly trusting, or is he wildly negligent in managing his vast fortune, which includes years of lavish endorsement deals in addition to his baseball salaries? Why didn't the team around him, including his agent, do more to prevent the possibility of the theft he claims?

Finally, where is Mizuhara? Anybody who knows isn't saying. He was fired in South Korea and apparently didn't travel home with the Dodgers. Japanese media have visited his home in Southern California to look for him. Although he was born in Japan, Mizuhara's life is in the U.S. — but his life will never be the same.