My guess is Elko will be in Chicago tomorrow. I personally would just option AV at this point to avoid the problem I lay out below. No need to DFA him - send him to AAA to try to get right. But I doubt the Sox actually do that to him.
At this point you pretty much have to put Elko on the roster. But if you do, one of AV, Elko or Quero have to be on the bench each day Quero does not catch. And once Lee returns, it only becomes more difficult to manage because it appears to me they're going to have to carry 3 catchers. Pretty tough to carry 3 catchers and 2 1B/DH only, and Lee likely isn't too far off from returning.
AV just sitting on the bench does not make much sense. You either need to play him, or send him to AAA and play him there.