The Sydney Swans will be without defender Callum Mills for the rest of the season, after an incident following training today.

Mills and some teammates were throwing a gridiron ball on the way back from a café in the Moore Park precinct when Mills tripped and fell.

Scans have since revealed he has suffered a broken foot.

Sydney Swans coach John Longmire said Mills will undergo surgery on Monday.

“It was a really unfortunate accident and unfortunately Callum has an operation on Monday and will be out for the rest of the year – it’s a bad break,” Longmire said.

“It’s something out of the blue and clearly very disappointing for him and us.”

Mills is one of two changes to the Sydney Swans line up for Saturday’s match against Brisbane.

Harry Marsh and debutant Ryley Stoddart come into the side, while Gary Rohan has been omitted.