Over the last week or so I've assumed Guyton would be back for the opener, but if Diggs is already back in practice and they're still a week away from starting the "practice week" for the game (first one will be Sunday), it would seem like Diggs should be able to go in some capacity.
I wonder if they have Bland/Elam play all the snaps when they're in base/2 CB alignments, and then only bring Diggs on for nickel/done with Bland shifting inside. Might be a decent way to ease him in, playing only maybe 40 or so snaps a game for a few weeks.