Golfer Phil Mickelson is gambling client in money laundering case: Sources

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Golfer Phil Mickelson is the "unnamed gambling client" mentioned in a plea agreement taken by another man charged in a money laundering case, multiple sources confirmed to NBC News on Tuesday.

Greg Silveira earlier this month reached an agreement with California prosecutors to plead guilty to three counts of money laundering to settle allegations he accepted a wire transfer of $2.7 million from a gambling client on March 26, 2010.

According to sources with knowledge of the case, that gambling client is Mickelson, who has won five majors, and was recently ranked by Forbes as one of the highest paid athletes in the world. The connection was first reported by ESPN's "Outside the Lines" on Monday.

Mickelson, 45, is not named in the plea agreement, he has not been charged, and is not implicated in any criminal activity or under investigation, sources said.

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Federal said in court documents that Silveria "participated in the operation of an illegal gambling operation." The document says that at the time of the transfer, Silveira knew the $2.75 million represented proceeds from illegal sports betting. He faces up to 60 years, but under sentencing guidelines would get anywhere from 10 to 37 months.

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Jerry C. Yang, a spokesman for the U.S. Attorney's Office for the Central District of California, would not comment. Neither would Mickelson's attorney, Glenn Cohen.

Sources said the California case is not related to a joint FBI/Securities and Exchange Commission investigation out of New York, which is examining whether Mickelson and Las Vegas gambler William "Billy" Walters used insider trading information from Icahn regarding investments in public companies.

Forbes said Mickelson earns more than $40 million annually from appearances and endorsements for such brands Callaway, Barclays, KPMG, Exxon Mobil, Rolex and Amgen.

He also promotes psoriatic arthritis drug Enbrel and last year re-signed a multi-year deal with Callaway last year to use the company's clubs, balls and bag during tournaments. The southpaw golfer has won five majors including three Masters, the PGA Championship and the British Open.