St Kilda key defender Sam Fisher has been cleared of structural damage to his jaw following a big collision in Saturday night’s 70-point loss to Sydney at Etihad Stadium.

The 34-year-old came from the ground midway through the third quarter after being cleaned up by Swans ruckman Toby Nankervis.

The dual Trevor Barker Award winner was taken to hospital for observation on Saturday night, before being discharged. He will be assessed early in the week to determine his availability going forward.

St Kilda Coach Alan Richardson lauded Fisher’s attack on the ball in the incident that ended the defenders game.

"He's gone to hospital just for some checks on his jaw … well have to wait and see on that one," Richardson said in his post-match press conference on Saturday night. 

"'Fish' committed strongly to the ball. It was one of those awkward bounces, and a collision coming the other way."

After producing a strong first half on triple Coleman medallist Lance Franklin, Fisher spent the first part of the third term off the ground due to some tightness in his lower legs.

Minutes upon return, the former All Australian was involved in the incident with Nankervis, which prematurely ended his night.

St Kilda’s disappointing night was marred further by injuries to ruckman Tom Hickey and small defender Jarryn Geary.

Geary injured his back in the warm up and was forced to be withdrawn late, while Hickey hurt his ankle early in the game, before fighting gallantly for most of the encounter despite being hampered.

"[Geary’s] a real warrior, he's a tough bugger, and he thought he'd be right," Richardson said.  

"Just as part of the tackling stuff they do inside he seized up a bit after some contact."