Naw, I don't think keeping him around benefits him or the team.
Look, the Avs, going into last year's camp, stood to ice as many as four rookies--or barely-not-rookies with Bigras--on the blueline last season (Mironov, Bigras, Lindholm, Siemens) along with the vets (Johnson, Barrie, Zadorov, Barberio). In hindsight this would've been a disaster given how poorly all those guys fared in the NHL. So a last minute waiver claim from Dallas ended up giving the team a viable depth defender who was capable of playing the 2nd pairing with Barrie. Then the team got Sammy and things really started to solidify, Z played alongside Barrie and Nemeth moved to an effective shutdown pairing with Barbs, which was huge for the 10-game win streak.
He skates quite well for a big guy, doesn't shy away from blocking shots point blank or physical play along the boards, his shot is actually a bit underrated (I mean, it's not great but I love the fact he doesn't have a gigantic wind-up, it finds the net) and he's improved his not-great puckhandling skills a fair amount. He was not frustrating me nearly much as he tended to last season.
Now, all that said, he was a fantastic interim measure. But that's all he is. He doesn't need to settle as a 7th guy if he can get decent coin and a bigger role elsewhere. Conversely, just like Blake Comeau, there comes a time when the interim guy serves his purpose, and you move on when the young players are ready. They're ready. Even if Z doesn't make it back I just don't see Nemeth sticking around. But I could be wrong...but if he stays I fully expect them to get rid of Barberio, or maybe even Zadorov. And I think, either way, that'd be a mistake.