With a prognosis on the injury - thought to be a cruciate ligament problem - expected on Wednesday and likely to rule out McKenna for the rest of the season, Davies is looking at the possibility of bringing in fresh faces to help with Forest's push for an automatic promotion spot.
"We are still in the process of talking to our staff, of identifying targets and seeing who is available. We are doing that as a matter of urgency," Davies told the Nottingham Evening Post.
"But this is a tough time of year to be trying to sign players. This is something you would ideally like to address in January.
"The key at this time of year is who is available. Clubs do not generally want to part with players at this stage of the season."