While Houston deserves every bit of criticism for the way they allowed things to disintegrate, the machinations of the draft cap can have a profound domino effect for teams holding high-slot-value draft picks. Thinking they'd be signing Aiken for $6.5M -- well under the $7.9M slot figure for the #1 overall pick this year -- the Astros had planned to apply some of their surplus cap money to signing Nix, their 5th rounder. And they had reportedly agreed on a $1.5M bonus. But when you fail to sign a pick in the first 10 rounds, you also lose the slot money assigned to that pick. So when the Aiken stuff fell apart, the surplus instantly vanished. And once they tallied up the bonuses already given to their other picks in the first 10 rounds, the Astros suddenly found themselves unable to give Nix more than $1.1 million without being subjected to penalties that would have cost them at least one future draft pick. Then when shit hit the fan with Nix, they tried to sign their 21st rounder (Marshall) by offering him Nix's money, but couldn't get a deal done (he's already enrolled at LSU).
Aiken and Nix were 2 of just 6 players in the first 10 rounds who went unsigned, along with RHP Andrew Suarez (WAS 2nd, #57), RHP Trevor Magill (STL 3rd, #104), OF Zach Zeiner (TOR 7th, #204), and 1B Austin Byler (WAS 9th, #274). The CBA doesn't allow teams to ask certain questions before the draft. But there's a reason that 309 of the 315 picks (98.1%) were signed, and it's because all of the stuff that's prohibited happens anyway. It's no secret. Figures are exchanged, if-then-else agreements are reached, and medical records often get reviewed. Even if teams don't know precisely who they're going to end up drafting, they have a pretty solid idea how they're going to split up the bonus pie to ensure they don't lose future draft picks -- or end up with wasted picks on unsigned talent, or the loss of slot money to spread around on other picks. For the questions over Aiken's UCL to linger unresolved until the final day of the signing period is absurd. Houston should have known about it well in advance, and should have adopted an alternate draft strategy if they were this unsure about his health.
As an aside, Aiken is just the third #1 overall pick not to sign in the half-century of the MLB amateur draft. He joins Danny Goodwin (1971, White Sox) and Tim Belcher (1983, Twins).