I think the Agger rumours aren't material cause all the sources seem to quote Sport. However, I was thinking about it, and just for discussion's sake let's say a 15m deal for Agger is reached (which is way too much, but wtv) I wouldn't be that displeased. I think the way to look at this is - Either we get our top class CB. A solid rock of a defender, to complete our back line, serve us well over the next 3-5 years at the very least, and put and end to this discussion for a while.
However, as we've discussed already, the guys we want, silva, hummels benatia etc. aren't coming one way or the other. If that's the case, I don't think we should just say fuck it, its them or nothing, but a player like Agger wouldn't be that bad. Pique Bartra Agger could be our CB options, and obviously there would be injuries and what not, maybe even requiring Mathieu or a B teamer to step in. Agger wouldn't be a big name who'd be a constant starter to bench either of Pique or Bartra, and he would accept a more secondary role. And FOR a secondary role, whatever I've seen of Agger, I quite like him.
Now it's true I've heard he's injured a lot, but I don't follow the EPL very much so not quite sure what the deal with that is...but purely as a player, I'd take Agger as a plan B, sort out the defence for now, at least until the transfer ban is over, and then reassess the situation after 2 transfer windows. For all you know, we might be in a much better position to get a solid CB, we might find one internally, we might have time to line one up, etc. and then we can take it from there..