Mayo forward Michael Conroy is set to miss their Connacht quarter-final clash with Galway on 19 May.
Conroy injured his shoulder while playing for his club Davitts on 20 April and underwent surgery last Friday.
He is expected to be out for eight weeks which means that he could also miss the provincial semi-final on 16 June if the Tribesemen are overcome in Salthill.
While last year's All-Ireland finalists are favoured to complete a hat-trick of provincial wins this summer, manager James Horan will be hoping that he will have his strongest squad to pick from.
Andy Moran is still sidelined after the injury he picked up in last year's All-Ireland quarter-final.
Along with Conroy, Chris Barrett, Brian Gallagher and Enda Varley recently picked up knocks