
The 25-year-old midfielder suffered the injury after being involved in an accidental collision during the game against Exeter City, which was held at the Swans' Fairwood training ground last weekend. In a major blow to Vitor Matos' side, Franco is now set to miss the opening two months of the the new Championship season, which kicks off on August 14.
In a statement issued on Thursday, the Swans confirmed the Portuguese star will miss the start of the campaign after undergoing ankle surgery.
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"Swansea City midfielder Gonçalo Franco will miss the start of the Championship season after undergoing surgery on an ankle injury," the statement read.
"A scan revealed the 25-year-old suffered ligament damage during a behind-closed-doors friendly. Franco has subsequently undergone a successful operation and the recovery process is expected to take 10 to 12 weeks."
Franco's absence is a significant one for Matos and his side, with the midfielder establishing himself as an influential figure in SA1 since his move from Moreirense in 2024.
He has since made 91 appearances for the Swans, scoring six goals, while he picked up two club Player of the Season awards following his debut campaign in Wales.
With Franco out, Matos has now lost two of his leading midfield players in quick succession, with Ethan Galbraith departing the club for Stoke City earlier this month.
Brighton and Hove Albion loanee Malick Yalcouye has also returned to the south coast of England after playing 36 times for the Swans last season, leaving little depth in central midfield for Matos to work with.
Swansea's only signings so far this summer have come in defence and attack, with centre-back Stephen Welsh and winger Moussa Yeo both joining the club.
However, Marko Stamenic, Jay Fulton, Melker Widell and Leo Walta all remain potential central midfield options for Matos.
Swansea's 2026/27 campaign kicks off on August 8 as they face Birmingham City in the Carabao Cup.
Their league season, meanwhile, starts with an away trip to Stoke on August 15.