The defender suffered a thigh strain in a practice match earlier in the week and is awaiting results of a scan.
However, boss Walter Smith expects him to be sidelined for a couple of weeks, which means his season could be all but over.
The Scottish champions have no other injury concerns as they bid to secure a second successive title at Easter Road on Sunday.
Gers (from): McGregor, Whittaker, Papac, Weir, Bougherra, Davis, Thomson, McCulloch, Lafferty, Naismith, Miller, Boyd, Novo, Edu, Fleck, Little, Smith, Alexander.
