The Sydney Swans will likely be without Isaac Heeney for the start of the season.

The 20-year-old missed Friday night’s win over GWS with a virus, which has now been confirmed as glandular fever.

Swans Head of Football Tom Harley says Heeney will be out of action for at least a few weeks.

“Clearly this is disappointing news for us and for Isaac as he has had a terrific pre-season to date,” Harley said.

“However, Isaac is receiving the care and rest he needs so we’re confident he will return to play early in the season and I’ve no doubt he will make a solid contribution when he returns.”