Collingwood has confirmed that defender Reef McInnes sustained an ACL injury and will be sidelined indefinitely.

McInnes left the field in the first quarter of last night's game, with scans today confirming the injury to his right knee.

EGM Football Charlie Gardiner said:

"We are incredibly disappointed for Reef. He had an enormous summer and showed some really strong form in the pre-season and opening rounds of the season in a new defensive role," Gardiner said.

"We were all hoping that he could have a consistent year and establish himself as regular part of our defensive unit but he is an outstanding person and we're confident he will bounce back from this latest setback. In the meantime, we will all rally around Reef and he will have our full support to ensure he makes a successful recovery."