SR / MC - Leonard Johnson?

MC / SR - Question about last weeks game versus the Ravens - I noticed that the team was rotating CB Dixon and even a safety Keith Tandy to play the the slot - one would have thought with the absence of Banks the team would have relied more on CB Johnson - instead he received a mere four snaps against the Ravens. The question if you guys know or could find out why? Could it be do to prior poor play or did he get benched for some other reason? And, now the team has signed a sub package CB who Lovie is familiar with in Frey - could this be the team is this down on Johnson and the end is nearing?