ST KILDA'S backline has been further decimated after captain Jarryn Geary was ruled out until after the bye.

The 29-year-old will miss games over the next fortnight against Sydney (Etihad Stadium) and Gold Coast (Metricon Stadium).

He is expected to be fit to face Melbourne in round 15 at the MCG.

Geary injured his left calf during the third quarter of the Saints' 13-point loss to West Coast at Optus Stadium last Saturday night.

"He'll miss three weeks, but one of them is a bye," coach Alan Richardson told Fox Footy on Monday night.

"He's a real warrior and wants to get back out there."

Geary has been very durable in recent years, missing just three matches since the start of 2015.

It leaves a threadbare backline to face the Swans. Jake Carlisle (suspension), Nathan Brown (right knee), Dylan Roberton (heart) and Sam Gilbert (right thumb) are also unavailable.