Soderberg is affordable if the cap is expected to increase a fair bit. That is only slightly in the NHL's control. Vegas will help increase it (early years they will produce more revenue than they cost, might change later on), but really it depends on oil prices and what the Canadian dollar does. If it rebounds to say 88 cents by next summer, the cap will go up a fair amount and would give the Avs a good amount of room to make some moves like Soderberg. How aggressive they want to be there is something only the organization can really answer.
As the Avs sit now, they have about 58.5m tied up for 15-16. That is with 13F, 6D, and 2G... With the cap at ~70m, they will have about 12m to spread across 2-3 spots.