Los Angeles-based McEwan's management, Golden Boy Promotions – run by former world champ Oscar De La Hoya – said no to a plan by Murray's promoter Ricky Hatton to switch the fight to Las Vegas.
And the bout between the two unbeaten fighters has now been axed from Hatton's 19 July Manchester bill as well.
McEwan, currently training in Edinburgh with Gilmerton welterweight Gary Young said: "I was keen to clash with Murray but I was amazed at their idea of moving the fight to Vegas.
"Even though Golden Boy Promotions are based in LA, they have enough savvy to know that an England versus Scotland scrap would draw more ringside fans in the UK."
McEwan is expected to fight in the US on 19 July on a Golden Boy promotion.
Meanwhile, Queensferry's Scottish light-welterweight youth champion, Chris McHale, has pulled out of the Scottish team fighting for British title glory in Cardiff on 9 July after damaging a rib while sparring with Josh Taylor.
McHale's injury means that hopes of an Edinburgh boxer winning a British Youth title in Cardiff now rest solely on the shoulders of Lochend featherweight Kevin Skey.