Richard Globensky, 39, faces up to 10 years in prison for transporting and transferring stolen goods, the US Attorney's Office for the Northern District of Illinois said.
US District Judge Sharon Johnson Coleman set sentencing for October 29.
Globensky stole Masters merchandise and memorabilia while working as a warehouse assistant for the Augusta National Golf Club, which hosts the prestigious tournament, between 2009 and 2022, the US Attorney's Office said in a statement.
Among the stolen items were the green jackets awarded to Arnold Palmer, Gene Sarazen and Ben Hogan for winning the Masters and documents and letters written and signed by Bobby Jones, the Masters co-founder, it said.
Globensky also stole huge quantities of Masters merchandise including shirts, hats, flags, watches, mugs and other goods from the Augusta warehouse, the US Attorney's office said.
Globensky sold the merchandise and historial items to an online broker in Florida for a total of $5.6 million.
