Not sure what websites statistics it was, but someone had posted it a few weeks back that Shanle was the WORST LB in the entire league against the pass according to their formula.
Shanle doesn't have it like he did last year and Dunbar should get a chance to play more. Maybe SP is just working him in as much as possible now to have him ready when he's really going to take over the spot.
The only problem I have with Dunbar is that he would play himself out of position. I have been trying to watch him when I notice him on the field and he seems to have gotten better at shedding blocks and being in better position which is a really nice sign.