St Johnstone midfielder Gary McDonald is expected to miss the remainder of the season.
The former Aberdeen man broke down in the half-time warm-up of last week’s game against St Mirren, and he is now waiting for confirmation that an operation is needed.
And that is likely to mean four months on the sidelines.
Manager Tommy Wright said: “Our season has already been marred by freakish, non-contact, serious injuries and on a disappointing note I have to report that it looks like Gary McDonald may need a similar operation to Steven MacLean. We will get this confirmed later on today.
“That will make seven serious injuries to key players throughout the season but I also feel that it highlights the strength of the squad and the level of achievement gaining top six has been.”
McDonald has featured in 27 of the club’s 32 Premiership matches this season, has 10 other cup appearances to his name and has scored vital cup goals at Morton and Raith Rovers.