That's fine if that's the goal. I'd argue the savings next season is pretty slim though. There's no way they can go into season with Stastney as the #3LD, can they? Aren't you going to spend $2-3M on something decent for that spot(especially for in case Walman gets injured)? Nurse+6D+7D is about $11.5M. Risto+new 6D+7D is like $8-9M?
$2-3M ain't bad, but seems like pennies when you're likely making the roster worse and pushing a good young player out of the lineup(Emberson) and losing another(Stastney).
Long term it's great, but making the roster worse next year is a mistake. People seem to be sure Nurse is going to return a decent player. Surely there's something other than Risto out there.