Hull winger Robbie Brady has withdrawn from the Republic of Ireland squad that will face Germany and Kazakhstan due to a groin injury.
The 21-year-old was called up by interim manager Noel King for next month's World Cup qualifying games but had on Saturday aggravated an existing groin complaint during a 1-0 victory over West Ham, in which he fired the only goal from the penalty spot.
A scan conducted on Monday evening determined Brady needed surgery on his groin and ruled him out of contention.
Stoke forward Jonathan Walters, meanwhile, 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 Football Association of Ireland 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.