Sydney star Lance Franklin is set to miss at least half of the AFL season after sustaining a serious hamstring injury.

Franklin hurt his hamstring at training on Wednesday and had a scan on Thursday.

He won’t be able to resume running for 3-4 weeks.

“I think it’s slightly worse than the injury he sustained last year when he missed about nine weeks, that might be an indication, but we just don’t know until he get into his rehabilitation,”‘ Swans’ general manager of football Charlie Gardiner said.