The Dubliner is set to be out for a number of months.
Robbie Brady looks set to miss the remainder of the Republic of Ireland's World Cup qualifying campaign.
Brady, who was named Ireland Player of the Year for 2024, missed the opening double-header earlier this month.
Preston manager Paul Heckingbottom has confirmed the Dubliner underwent surgery on a calf problem and is set to be out of action for 'a number of months'.
Ireland resume their campaign against Portugal and Armenia in the middle of next month.
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