I really can't do much better than this article on Fangraphs, which does a great job of covering all angles in the ugly Aiken/Astros saga. So, instead of trying to compete, I thought that I would try and add a little bit. Most likely not much, but here goes.
Firstly, this is not likely to be a game of chicken - if it is, it is a ridiculous one, and I cannot believe the organisation (or any organisation) would be so stupid as to try something like this. If this is some kind of deliberate tactic, it is plain dumb.
Secondly, it is clear that Brady Aiken is not currently hurt. However, the Astros have identified something that worries them for the future. It seems to be described as an unusually small ulnar collateral ligament which isn't torn. I am not sure of the implications of an unusually small ligament (if that is in fact the abnormality), but because the new ligament is not grafted on to the old ligament (i.e. not sewn straight in to the existing ligament, using the existing insertions), there cannot be concerns about the size of the ligament and the strength of the insertion itself. The concerns are more likely to be around the anatomy of the elbow itself, but the exact nature of those concerns are uncertain.
In summary, something that the Astros have seen have caused them to take a second look, and it is more than simply a tear in the UCL. It has now become a risk-management issue - are the future medical concerns significant enough that the Astros want to alter the deal significantly? It seems yes.
Thirdly, the Astros are in a tough position here. They cannot afford to whiff on (another) number 1 pick. They also cannot reveal the medical information of anyone without their consent, and it is highly unlikely that Mr Aiken would provide said consent, as he may be eyeing a contract with the other 29 teams at some stage in the future. Providing consent to release medical records would be a colossally dumb thing to do.
So the Astros are in the position where they have to stay silent, and wear whatever the people around this want to throw at them. This is a position that hospitals and medical practitioners find themselves in all the time. Disgruntled patients fairly often run to the media, kick up a storm, and the medical people cannot reply publicly in detail, because commenting on the situation will certainly involve revealing private and confidential medical information. And this release of confidential medical information is never justified (the law simply does not allow this) no matter what the agitating party alleges happened. A lawsuit would certainly result from this, and this would likely cost the Astros much more than $6 million.
So essentially, Casey Close, Brady Aiken's trainer, his family doctor, his yoga teacher, and the guy that walks their dogs can lob whatever innuendo grenades they want to into the Astros' compound, and there is really nothing they can do to retaliate. They simply have to wear the public relations disaster. The simple fact is that the "Astros suck" narratives will stick that little bit easier now.
(People don't really appreciate the shades of grey that are existent here. Often in medicine, the more you look, the more complicated things get. It is the opinions of the experts that the various parties are relying upon here, and experts often disagree. Experts also don't have crystal balls. Adding an additional wrinkle is that it is likelihood of future injury, not current injury, that is being assessed here.)
Fourthly, I am interested in Casey Close's use of the word "asymptomatic" here. In medicine, you have signs (abnormal features that are revealed on examination) and symptoms (the things that the patients report as abnormal). It is clear that Brady Aiken is reportedly asymptomatic - he has no symptoms of elbow difficulties, or at least isn't admitting to the presence of symptoms. So Close's use of the word asymptomatic is technically correct, but it does not mean that there are no examination findings (or signs) that indicate abnormal anatomy. Kind of a neat way of wording things to the advantage of your client whilst obscuring the real picture.
Finally, what this really boils down to is one question. Is the current pick (Brady Aiken with elbow warts and all) a better choice than whomever they can get with the 1-2 pick next year? This is the opportunity cost equation. For those pundits out there that say "just sign him, and get Nix and possibly Mac Marshall as well" - if the Astros believe that there is a good risk that Aiken will fall over in the future - then you are actually giving up the second overall pick in the 2015 draft for Nix +/- Marshall lottery tickets.
So the question then becomes: Does Aiken (with risk adjustments) and Nix, with possibly Marshall project better than (likely) two of the top five picks in 2015, plus any slot-bonus shenanigans that you can magic-up in 2015 with a massive slot bonus pool.
Imagine, if you will, the latter scenario. The Astros have pick number 2 and (say, conservatively) pick number 4, have a draft pool approaching 17-18 million, and potentially the opportunity to throw enough money at two or three Mac Marshall's after the 20th round. Which is a great situation for a Front Office to be in.
If they are still around for the 2015 draft, that is. Because the public-relations fallout may mean that Luhnow's tenure becomes unsustainable.
(PS: not suggesting that having a massive draft pool in the 2015 draft is the primary motivation for this situation.)