Due to heavy rain and a drop in temperatures, the surface at McDiarmid Park will be checked before the Jambos travel up the A90 to Perth.

For the hosts, Zander Clark and Callum Booth are rated as 50-50 as they battle with respective calf and groin problems. Nadir Ciftci and Michael O'Halloran are fit again after hamstring injuries but Cammy MacPherson, Chris Kane, Shaun Rooney, Craig Bryson and David Wotherspoon are out.

Hearts have a near full-strength squad available as they look to win in Perth for the first time in a decade. Michael Smith returned to the side last weekend after issues with his back and should be available, meaning Craig Halkett is the only confirmed absentee as he works his way back from a hamstring injury.

Goalkeeper Zander Clark is struggling with injury for St Johnstone.

Probable St Johnstone team: Parish; Cleary, Gordon, Kerr; Brown, Hallberg, Butterfield, Gallacher; Crawford, Middleton; Hendry.

Probable Hearts team: Gordon: Sibbick, Souttar, Kingsley; Smith, Devlin, Baningime, Cochrane; McKay, Boyce, Simms.

St Johnstone v Hearts: Pitch inspection, Saints sweat over key player's fitness, one player out for Jambos, probable teams