These walleyes will be tight to the bottom, lying in the holes between rock and cuts in the bottom. They may be feeding, or waiting in ambush to find an easy meal that comes their way. When fishing structure, you have to be able to stay tight to the structure or your lure presentation will not be in the strike zone of the fish. Move just a boat length away and you will be out of luck. One of the very first places I look and concentrate my efforts is on the flats.
Flats are the least interesting types of structure in a lake.
There are no breaks, holes, edges, just flat bottom. But seemingly featureless flats hold most of the active walleyes during most yearly periods. With that definition there is always an exception. The exception in this case are the mud flats of Mille Lacs. Most anglers believe that the bigger fish move to the shoreline in the fall, but the mud flats of Mille Lacs hold fish all year around and these big fish stay and feed during the fall months.