RETIRING St Kilda champion Nick Riewoldt will miss Sunday afternoon's crunch clash with Melbourne at the MCG after he was ruled out with concussion.

The club is hopeful Riewoldt will miss just one game.

Riewoldt, 34, was concussed in a head clash with West Coast midfielder Dom Sheed in the final term of last week's eight-point win.

The former skipper didn't return to the game and while coach Alan Richardson was confident in the immediate aftermath Riewoldt would be fine, he didn't train on Thursday at Seaford.

Football manager Jamie Cox told saints.com.au Riewoldt was not back to full fitness and will miss this week's clash.

"Nick copped the knock late against West Coast and hasn't quite got back to 100 per cent," Cox said.

"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."

If St Kilda don't make finals, it leaves Riewoldt with two games before his career ends.

The Saints are in 11th spot with a 10-9 record.