Dougie doesn't look anything like what he did in the first few weeks of the season. He was fast, dynamic, making reads and using his vision. Now he looks slow and lazy and lethargic. It really can't be anything other than injuries.
Honestly, if the RHD situation wasn't as sad as it is I think he might have been shut down for the year. They clearly don't trust Subban or Walsh and there's literally no other options.