I do have an argument for that.
I broke my tibia 4 months ago and wasn't able to walk for 5 weeks. About 1-2 weeks after I started walking I could do light prowler work. This was about 2 weeks before I was able to do squats with very light weight and almost 4 weeks before I could do squats as much weight as pain tolerated.
So in short, the prowler work was quality strength work I could do on an injured limb that was relatively low stress/low impact. It also greatly increased the quality of my later (current) rehab, as I had already gained some strength back before I started really getting back into lifting.
obviously I'm not a PT or a trainer, this is simply anecdotal evidence that may or may not persuade the PT department.