St Kilda champion Nick Riewoldt has been ruled out of this Sunday’s crucial encounter with Melbourne at the MCG.

The 34-year-old sustained a concussion following a head clash with West Coast midfielder Dom Sheed in the fourth quarter of last weekend’s thrilling win at Etihad Stadium.

Saints GM Football Performance Jamie Cox confirmed the news on Thursday afternoon and said the club is hopeful Riewoldt will only miss one game.

“Nick copped the knock late against West Coast and hasn’t quite got back to 100 per cent,” Cox told saints.com.au on Thursday.

“As he hasn’t passed the subsequent concussion tests he won’t face Melbourne this weekend.

“We’re hopeful Nick will only miss one game but he will go through the standard concussion protocols next week before being declared available for selection.”

The six-time Trevor Barker Award winner announced his decision to retire at the end of this season last Monday after 17 seasons of distinguished service in red, white and black.