Partick Thistle manager Alan Archibald expects to have to replace some key players over the summer.
Defender Conrad Balatoni, 24, goalkeeper Scott Fox, 27, and midfielder Kallum Higginbotham, 25, have been offered new deals.
But Archibald, whose side ended their season with a 0-0 draw with Motherwell, told BBC Scotland: "Those three look like they'll be moving on.
"We need to strengthen. It's going to be a tougher league next year."
Pressed on Fox's situation, Archibald responded: "I think Scott's rejected his offer at the moment.
"We'll struggle to hold on to him, he's been a great servant to the club. Fantastic performances - another clean sheet today.
"There's a little bit of hope but it's highly unlikely we'll hold on to him.
"We're just waiting for a couple of the guys to come back with their answers. We'll find out probably in the next couple of days then we have to move on to our own targets.
"We've got most of the other boys tied up. We've got a good spine of our team and we've got younger boys coming through as well."