Aberdeen will be without Scott Wright for the visit of St Johnstone in the Ladbrokes Premiership.
The Dons striker could be out for the season with a cruciate injury ligament sustained in training on Monday.
Midfielder Holt and right-back Ralston signed on season-long loans from Rangers and Celtic respectively.
Veteran midfielder Liam Craig is ruled out through injury.
Provisional Aberdeen squad: Lewis, Logan, Leigh, Vyner, Considine, Devlin, Ojo, Gallagher, McGinn, Hedges, Ferguson, Bryson, Cosgrove, McLennan, Main, Wilson, Anderson, Campbell, Cerny.
Provisional St Johnstone squad: Clark, Duffy, Ralston, Tanser, Gordon, Vihmann, Kerr, Holt, Callachan, Davidson, Swanson, McCann, Wright, O'Halloran, Kane, May, Hendry, Kennedy, Wotherspoon, Parish.