Craig Dargo will not be able to make his St Mirren debut against Motherwell because he is still sidelined with injury.
The striker will have to sit out of Saints' season opener on Saturday because he has yet to recover from a knee strain sustained in a friendly against Clyde.
Dargo, 29, turned down a number of clubs, including Motherwell, to join Saints and much is expected of the forward after he scored 32 goals in two seasons with his previous club Inverness.
St Mirren manager Gus MacPherson has admitted the club's disappointment at the loss of Dargo.
"He is out, he has got a strain in his knee so he will miss Saturday," said MacPherson.
"It's a blow but there is no-one that is more disappointed than Craig.
"He is desperate to come in and make an impression.
"But for the first game of the season we are not going to take any chances with him.
MacPherson is hopeful the Motherwell match will be the only game Dargo misses, but he insists the club will not rush the decision.
"It could be but we will be led by the medical team on that one," MacPherson added.
"It's just rest, there is not a lot we can do with the injury."
MacPherson is also unlikely to complete the signings of Israeli striker Roy Dayan and Argentinian left-back Franco Miranda in time for the first game of the season.
The club are trying to gain international clearance for the players after they both impressed while on trial.
"Everything has been agreed with the players, it is now just a case of trying to get the paperwork done and get agreements with the respective clubs," MacPherson concluded.