Holl and LoVerde were two of the better defensemen in the AHL last year and are there to help our younger defense. Both should be there above Durzi, and it's not like they can go anywhere else besides the NHL (and neither are suited for that). Subban has a contract that can not go to the ECHL. Liljegren is the only one who can be sent to the ECHL, and that's not going to happen. If Dubas really planned on having Durzi anywhere near the AHL, he would not have signed Subban... Especially since they play a very similar game. Really, signing Holl for two years was also a good indication. Next year, LoVerde is probably gone, Subban is probably gone or traded, and Liljegren is probably moving up to the Leafs to replace Hainsey. That leaves three spots for Durzi, Hollowell and Lindgren as they probably planned. Rasanen will eventually work his way in there as well. In the meantime, Lindgren will probably get loaned to the Liiga for one more year, because he did have one more year on his original deal. Rasanen is already in the KHL. Durzi and Hollowell play in the OHL for one more year, which is not ridiculous. Both have a few things they could work on before going pro.
As for the off side, the LD is harder to crack. Borgman, Rosen and Marincin would all play long before Durzi, never mind Durzi on his off side. That is three NHL quality players you are talking about. Nielsen can go to the ECHL, but he's already the #4 on that depth chart, and is far too good for even that, never mind the ECHL. He'd be traded before getting sent down, even if it is like what happened to Valiev.
The Leafs had no problem sending Brooks back for his OA year after drafting him. No reason to believe Durzi should be any different. We had less depth at center at that time than we did RD right now, and he had a more impressive pre-OA season than Durzi did.