TOUGH St Kilda midfielder David Armitage will miss at least a month after groin surgery.

Armitage, 28, played in round one against Melbourne but missed the next two games, returning the following week in the win against Collingwood but pulling up sore after the game.

He picked up 17 disposals in the clash with the Magpies in 69 per cent of game time.

St Kilda football manager Jamie Cox told saints.com.au that Armitage will not run for two weeks.

"He has had to undergo an adductor release surgery," Cox said.

"Dave won't run for a couple of weeks and is expected to miss at least a month.

Armitage was missed in the 38-point loss to Geelong last Sunday as Cats skipper Joel Selwood put in a dominant performance.

The Saint was hampered last year by a back complaint that affected his running.

Fellow onballer Koby Stevens suffered a concussion in the VFL last Saturday and will have a fitness test on Thursday.

"Koby copped a knock to his head in the VFL and sat out the second half of the game," Cox said.

"He has pulled up well from the knock but will need to prove his fitness on Thursday before being declared fit for the weekend."

Young forward Josh Battle will miss a couple of weeks with bone bruising in his left knee. Last year's No. 39 selection was also hurt while playing for Sandringham.