St Johnstone midfielder Chris Millar is out for up to three weeks after picking up a groin injury.
Millar featured in Saints' opening two games of the season but will miss Saturday's visit of Dunfermline and may not return to action until September.
"It is bad news for Chris and for the team," manager Derek McInnes told the St Johnstone website.
"Hopefully with the right treatment and rest it will not prove to be an extended absence."
Meanwhile, striker Sam Parkin continued his recovery from a broken ankle by playing in two practice matches last week.
"Full fitness is still some time away but the big Englishman is certainly heading in the right direction," said the Saints website.