The point guard played through the injury in the team's defeat to the Charlotte Bobcats last night, but managed just 12 points in almost 30 minutes on court.
The head coach told reporters: "He's struggling. He couldn't move and you kind of had a feeling, and I was right that they were going to go [Jannero] Pargo and [Ramon] Sessions and start going pick-and-rolls. He's trying but you could see him laboring up and down the floor. It's tough. At some point, we may have to make a decision to sit him down as well."
Collison has started two games since sustaining the injury in an awkward landing against the Indiana Pacers.