ST KILDA captain Nick Riewoldt has flown back to Melbourne on Sunday morning accompanied by his wife, with the club saying he is "in good spirits".

The 32-year-old suffered a sickening head clash during the Saints' 46-point loss to Adelaide at Adelaide Oval on Saturday.

He was cleared of any structural damage to his head, but spent the night in hospital.

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Riewoldt remains in doubt for next Saturday's home clash against West Coast. 

He was knocked unconscious after clashing heads with Crow Brodie Smith in the first quarter and was taken from the field on a stretcher.

"They're looking at him from a concussion point of view, just for observation purposes," coach Alan Richardson said post-match.

"He's up, cracking jokes with a couple of the staff, he's feeling OK but he does need to stay in for the night. 

"Riewoldt took 30 more marks than anyone in the competition last year and he is a player that can score goals and connect the defence to the offence, and we have struggled without him. 

"Our best performances have been with him in the team." 

The Saints had a horrible run with injuries on Saturday afternoon.

Before the game Jarryn Geary (corked thigh) and Leigh Montagna (hamstring tightness) were late changes and youngster Jack Lonie was also concussed and subbed out in the first quarter.

But Richardson refused to use the injuries as an excuse for the loss.

He was happy with Billy Longer in the ruck and David Armitage and Jack Steven were again impressive but overall, St Kilda was dominated by Adelaide in the midfield, losing contested possessions (146-118) and clearances (42-29). 

Brodie Smith has been taken to the rooms and Nick Riewoldt carted off after this clash. #AFLCrowsSaints

— AFL (@AFL) May 16, 2015

"The reality is, they would've helped, but it was our inability to handle the Crows pressure," Richardson remarked. 

"We just didn't cope with that ball that needed to be won.

"They just beat us in the contest.

"We need our next group of midfielders to carry more of the load; I refer to (Luke) Dunstan, (Jack) Newnes and (Jack) Billings."

WATCH: Alan Richardson's full post-match media conference

While the Saints lost the midfield battle, they still managed to generate more inside 50s (56-52).

After Riewoldt's injury, Josh Bruce played a lone hand up forward with five goals and 12 marks.

Richardson lamented missed opportunities and the ease at which the Crows scored their goals. 

"All those easy goals out the back was our inability to stop it at the source when we had numbers at the ball," Richardson said. 

"We certainly missed too many and when we are a team that needs to make the most of [its] opportunities, we should've done better." 

Richardson said No.1 draft pick Patty McCartin could come in for next week's clash against the Eagles, depending on Riewoldt's recovery.

Jack Sinclair will return to the rookie list with Seb Ross coming back from his long-term hamstring injury.