Mayo will have to challenge for honours this season without full-back Kevin Keane.
The defender suffered an anterior cruciate ligament injury playing for Westport in the All-Ireland intermediate final victory last weekend.
The 26-year-old was stretchered off after 11 minutes of play at the weekend and scans after the game revealed the injury.
Speaking on MidWest Radio, Westport manager Damien Loftus confirmed the ACL injury.
Keane's injury is a set back for Mayo boss Stephen Rochford as he tries to claim an All-Ireland for the green and red.