Honestly, it would take over 4.2M in an offer sheet to fetch a 1st rounder. I doubt anyone offer Dach that much but if they do we let him go and laugh our way to the bank. My opinion on his market value would fetch a 3rd rounder. Honestly, between a 3rd rounder and Dach given 2 years to try to sort himself out, I'd give him a shot. He can't really hurt the rebuild at 1.5-2M AAV, and if he gets better it helps it.
If someone offers him 2.1M to 4.2M is where things get dicey. Do we take a 2nd rounder for Dach or keep him? What is the *max* the 'hawks are willing to swallow to keep him vs. letting him walk for a 2nd rounder? Bird in the hand and all that.
I do agree with
@Granada though: given the scorched and salted earth mindset of Stan, Byram might not have developed here properly...after all, Dach hasn't. Still, my opinion is that your defense isn't set until it is, and if you overload on D-prospects and more turn out to be good than you can keep, they can be flipped at good value, so on its face picking Dach over Byram was dumb... irrespective of whether or not Byram would have developed. D was and still is a much more pressing need, and Stan counted his weasels before they popped.