Ross County striker Mustafi sidelined for a month
The 23-year old Swiss striker, who is on loan from Grasshoppers until January, has suffered a broken toe and will not be available until around mid-October.
"It's a big blow because Orhan is a strong player and is technically very good," said Staggies boss Derek Adams.
"We are going to miss him for about three to four weeks."
Since arriving at Victoria Park, Mustafi has made five appearances including a goal in the League Cup loss to Stranraer last month.