Defender Liam Gordon could return after staying on the bench at Ayr on Saturday following his concussion injury.
Midfielder Murray Davidson (fractured arm) remains on the sidelines.
Motherwell have no fresh injury problems for the Ladbrokes Premiership clash.
Former Saints striker Tony Watt played 45 minutes for the reserves on Monday following his recent arrival and is likely to start on the bench.
St Johnstone provisional squad: Clark, Ralston, Duffy, Booth, Tanser, McCart, Kerr, Holt, Swanson, Craig, Gordon, McCann, Kane, May, Wotherspoon, Hendry, Butcher, Jones, Wright, Parish.
Motherwell provisional squad: Gillespie, Tait, Grimshaw, Carroll, Hartley, Gallagher, Mugabi, Campbell, Donnelly, O'Hara, Polworth, Long, Hylton, Seedorf, Ilic, Ndjoli, MacIver, Aarons, Watt, Carson.