ST KILDA could face a financial sanction for bringing in Luke Delaney for Saturday night's clash against the Western Bulldogs after defender Sam Fisher's withdrawal.

On Saturday, Fisher was withdrawn from the side due to back soreness, with fellow key defender Delaney, who was not named as an emergency, named as his replacement.

The Saints could be fined up to $20,000 for bringing in a player from outside their emergency-listed players on match day.

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The swap of Delaney for Fisher would be considered a like for like replacement considering they play in similar positions.

St Kilda football manager Jamie Cox said the Saints informed the League and the Bulldogs of the change at the earliest possible stage.

"Unfortunately Sam Fisher experienced back problems this morning and will be replaced like-for-like in the side by Luke Delaney," Cox told the club's website.

"Delaney played well on Tom Boyd last time the two teams met earlier in the season so we feel he is the best available match-up."

Had the Saints informed the AFL, the Bulldogs and media of the team change on Friday, then they would not be facing a potential sanction.

Blake Acres, Daniel McKenzie and Cameron Shenton were listed as emergencies when the teams were named on Thursday night.