The clash at PPL Park in Chester, Pennsylvania, is scheduled for July 30, with the Potters flying back to the United Kingdom 24 hours later.
They head out to the States on July 22 and face two other Major League Soccer sides before the game against the Union - Houston Dynamo on July 24 and FC Dallas on July 27.
COMMENT RULES: Comments that are judged to be defamatory, abusive or in bad taste are not acceptable and contributors who consistently fall below certain criteria will be permanently blacklisted. The moderator will not enter into debate with individual contributors and the moderator’s decision is final. It is Belfast Telegraph policy to close comments on court cases, tribunals and active legal investigations. We may also close comments on articles which are being targeted for abuse. Problems with commenting? firstname.lastname@example.org