After two great weeks on the ATP Challenger Tour, Marcos will make his ninth appearance at the US Open, which begins on Monday, 25 August, in New York.
Marcos enjoyed his best showing at Flushing Meadows last year, when he reached the third round, beating Kevin Anderson before falling to Stan Wawrinka. In 2006, he played one of the most dramatic matches of his career in the Arthur Ashe night session, extending Andre Agassi to fine gripping sets in the second round.
The main draw for the US Open will take place on Thursday, 21 August.
