Jamaica winger Omar Daley comes into the Motherwell squad after completing his move to Fir Park in midweek.
Shaun Hutchinson is out for about a month after suffering an ankle injury at Celtic Park last weekend.
Steven Saunders remains out with a long-term Achilles injury.
St Johnstone midfielder Jody Morris will miss out with a hamstring injury.
Perth boss Derek McInnes revealed he is at least three weeks away from getting his other injured players back.
Callum Davidson (calf), Murray Davidson (knee) and Sam Parkin (ankle) are all still out and will not be back until October.
Motherwell (from): Randolph, Hateley, Clancy, Craigan, Hammell, Jennings, Lasley, Law, Humphrey, Murphy, Higdon, McHugh, Page, Lawless, Carswell, Smith, Daley, Hollis.
St Johnstone (from): Enckelman, MacKay, McCracken, Anderson, Wright, Maybury, Millar, Robertson, Adams, Gibson, Craig, Sandaza, Sheridan, Finnigan, Mannus, Caddis, May, Rodger.