You don't trade 1st round picks to make room for a college UFA.
Well, if Sustr is a MUCH better prospect than say, Maatta, then you certainly do look to sign the better player and trade the lesser one. It's a free asset, it's like getting a free draft pick.
A good question is: if Sustr were in the draft this year, even at his age, where would he project to go? If he would only be a mid-round pick because his upside might only be a bottom pairing Dman who can play on the PK, then it's no biggie if we miss him and may not be worth signing at all. If, however, his upside is closer to that of a Zdeno Chara or Tyler Myers, that would probably make him our #1 prospect in our entire system. If the latter is the case, you sign that player if you have the chance -- regardless of who is in the system or where those players were drafted.
Yeah, you don't trade the guys with pedigree for a college free agent, but at the same rate, who is to say our defensive depth doesn't change as soon as this season? What if Shero goes out and trades a defensive prospect or two to get wingers? All of a sudden, there's way more room for him.
He won't hop Morrow, Despres, or Bortuzzo, but he very well could be better than any of the rest who are in the AHL now, and Maatta and Pouliot will probably be back in Jr. next season if eligible (which I don't know if they are).
Both Pouliot and Maatta are junior eligable next season, so both have to go back to junior (unless Maatta went back to Finland). And regardless of whether we sign Sustr or not, we know that at some point -- whether it's this season, in the summer/at the draft, or next year -- one or two of our Dmen prospects will be moved for help up front, and/or someone on our current roster (Martin/Orpik). That will open up room for guys like Dumoulin/Morrow/Harrington to push for jobs, and could even open up a spot for a guy like Sustr on the bottom pairing in the NHL, or at least give him a bigger, top-3 role in WBS.