Brady has made an impressive start to the season with Hull and was included in interim coach Noel King's squad for next month's 2014 World Cup qualifiers.
However, the 21-year-old has now withdrawn from the squad after the Football Association of Ireland confirmed Brady will require groin surgery following a scan on Monday evening.
He had aggravated the injury during Hull's 1-0 win over West Ham on Saturday when Brady scored the only goal of the game from the penalty spot.
Meanwhile, Stoke forward Jonathan Walters remains available to King for the Group C games after undergoing a scan on the groin injury he sustained in the Potters' 1-0 Premier League defeat to Norwich.
A statement from the FAI confirmed the 30-year-old's condition would be "assessed as the week progresses".
The qualifiers mark the first games of the post-Giovanni Trapattoni era after the Italian was sacked earlier this month.
Ireland Under 21s coach King is now holding the fort while former international Ray Houghton and high performance director Ruud Dokter carry out a comprehensive assessment of the managerial market in an attempt to identify the best man for the job.