The former interpreter of Japanese baseball star Shohei Ohtani pleaded guilty to tax and bank fraud charges at a courthouse south of Los Angeles on Tuesday.

Ippei Mizuhara, 39, is accused of stealing nearly $17m (£13.3m) from Mr Ohtani – who plays for the Los Angeles Dodgers – during the years he was employed by the top athlete.

Mr Ohtani is one of the biggest names in modern baseball. He signed a record 10-year, $700m contract with the Dodgers before the 2024 season, becoming a face of the franchise and Major League Baseball.

Prosecutors have said that Mizuhara used the baseball player’s money to pay off his mounting gambling debts.

The guilty plea is part of a deal the ex-interpreter entered with prosecutors in exchange for a reduced sentence.

The case has been the subject of much attention from baseball fans in Japan and America since news of the allegations first broke in March.

At Tuesday’s hearing at a federal court in Orange County, Mizhuara reportedly said that he fell into major gambling debt. He said that the only way out was to use money he wired from Mr Ohtani’s account.

Prosecutors allege the ex-interpreter had called bank officials and falsely identified himself as Mr Ohtani “to trick employees into authorizing wire transfers from [Mr] Ohtani’s bank account to associates of the illegal gambling operation”.

They have also accused him of tax fraud.

“The extent of this defendant’s deception and theft is massive,” US Attorney Martin Estrada said last month when laying out the charges.

“He took advantage of his position of trust to take advantage of Mr Ohtani and fuel a dangerous gambling habit.”

The bank fraud charge is punishable by up to 30 years in prison, and he could face up to three years for the tax fraud charge.

Mizhuara pleaded guilty to both.

A sentencing hearing has been scheduled for 25 October.

Mizhuara was fired in March as news of the allegations emerged. At the time, Mr Ohtani, 29, said he was “saddened and shocked” that someone he had trusted had “done this”.

Mizuhara had been a constant companion since the baseball star – now a two-time winner of the American League MVP award – began playing in the US in 2018.

Mr Ohtani, who does not speak English, has relied heavily on his interpreter, from help with media interviews to banking and working with his financial advisors.