Mayo have been dealt a big setback with the news that star forward Cillian O'Connor will require an operation on the Achilles injury he suffered in Sunday's Allianz Football League win over Clare.

O'Connor finished with a personal haul of 1-04 despite exiting the fray just before the interval at Cusack Park as Mayo secured their return to the top flight but will now be absent for an as yet unspecified period of time.

A statement from Mayo GAA read: "Following last Sunday's NFL game versus Clare GAA all injured players received further assessment with the Mayo medical team.

"Cillian O'Connor sustained an Achilles tendon injury that will require a procedure this week.

"We wish him well and look forward to seeing him on the playing field again as soon as possible."

Mayo commence their Connacht SFC campaign against Sligo at Markievicz Park on Saturday week.

O'Connor is the all-time record championship scorer and bagged 5-40 in Mayo's five-game run to the All-Ireland final last year.