Mayo have potentially suffered a huge blow ahead of the inter-county season, with a knee injury to Aidan O'Shea.
Last year's captain picked up the knock during Tuesday's first collective training session, after the ban on training was lifted.
The Mayo News say O'Shea sustained the injury innocuously during the county's session at MacHale Park in Castlebar.
The 30-year old Breaffy man will have the injury assessed by the Mayo medical team in the coming days, but is also expected to undergo a scan on the knee later this week.
Mayo manager James Horan will be hopeful the injury doesn't break O'Shea's streak of 58 consecutive championship matches.
They're due to play Sligo in a Connacht senior quarter-final against Sligo in just under nine-weeks' time. Should they come through that unscathed, Mayo will play Leitrim in the semi-finals.
O'Shea captained his county to their first provincial title in five-years last November, when Mayo beat Galway by a single point at Pearse Stadium.
Mayo are slated to return to action on Saturday May 15 when they play Down in Division 2 of the Allianz Football League.
O'Shea will hope his injury is not as serious as the one suffered by county teammate Jason Doherty. He's been out since October when he tore the anterior cruciate ligament in his left knee, also during a training session.
Meanwhile, Colm Boyle had six months on the sidelines after sustaining a knee ligament injury of his own in an Allianz League clash with Dublin.