Dundee United will be without Danny Swanson, who has strained his medial ligament and could be out for up to two months.
And he is likely to be joined in the stand by defender Sean Dillon, who is a major doubt with a calf problem.
Peter Houston's side will be boosted by the return of Keith Watson, however, after he missed out against Aberdeen last weekend.
Long-term absentee Scott Severin remains sidelined with a broken leg.
St Johnstone will give Cillian Sheridan every opportunity to recover from a hamstring injury ahead of the game.
The striker was forced off 20 minutes into last weekend's win over Inverness and will receive treatment up to the last minute.
Sam Parkin (ankle) remains on the sidelines but St Johnstone report no other injury problems.
Dundee United (from): Pernis, Douglas, Dixon, Watson, Kenneth, Gunning, Smith, Allan, Flood, Rankin, Armstrong, Robertson, Mackay-Steven, Hilson, Dow, Russell, Daly, Dalle Valle, Banks.
St Johnstone (from): Enckelman, C Davidson, Maybury, MacKay, Anderson, Morris, Gibson, Craig, Moon, Millar, Sheridan, Sandaza, Haber, Caddis, May, Mannus, Durnan, M Davidson, Wright.
