ST KILDA midfielder David Armitage has been ruled out Saturday's clash against West Coast at Domain Stadium because of a groin injury. 

The experienced midfielder pulled up sore from the Saints' loss to Melbourne in round one and will join former captain Nick Riewoldt on the sidelines for at least one week. 

"It’s not one we think is too serious and he should only miss a week or two," Saints football manager Jamie Cox told saintsfc.com.au.

It will be just the second game Armitage has missed in the past 56 matches. 

The Saints could be boosted, however, by the return of veteran half-back Leigh Montagna, who has recovered from a calf injury. 

Cox said the 33-year-old played solid minutes in the practice match between VFL affiliate Sandringham and Port Melbourne on Sunday.

Young forward Paddy McCartin, who was a late withdrawal against the Demons with hamstring troubles, shapes as the most likely replacement for Riewoldt after having his game time managed in the VFL trial game. 

"(He) had some good minutes in the VFL on Sunday and looks to have shaken off any troubles and should also be in the mix for selection," Cox said.