Can company demote driver based on insurance company?

I have a job as a power lineman. I had an unavoidable accident about a year ago turning over a bucket truck costing the company money.

Now I'm off workers comp and cleared for work. Upon my return, the company wants to demote me, change my job title where I'll make less.

They say it's because their insurance company won't let me drive a cdl truck. I was cited but was reduced to a non moving violation.
Could this be true? Thank you