Theres also taking an overpaid roster player back. Salary retention is definitely not a must and will cost more since the ret is dead cap space. An overpaid roster player is a tradeable or useable piece. If Vegas can fit Eichel's 10M with no ret, teams can fit Miller's 5.25M with no ret
Well, taking back overpaid players is essentially the same as retention for the team sending the overpaid player back (from a cap point of view). Of course, it depends on how much term is left for the overpaid player.
We shall see though. Last year, significant retention was required for:
Carter to PIT
Foligno to TOR
Rittich to TOR
Noesen to TOR
Janmark to VGN (actually 2 teams involved to get higher than 50% retention)
Raffl to WSH
Savard to TBL (2 teams involved to get higher than 50% retention)
The only "big" names to be traded without retention:
Mantha (Caps sent Vrana and Panik back. Caps also had to move Siegenthaler in a separate deal).
Bennett (an RFA making just over $3M and Florida had plenty of space)
Hall (Boston had space).
I very well could be wrong, but my personal view is that retention won't add as much value as some think it will. It will add some, but when a lot of teams are going to require it (or require to send assets back or make other moves), it's not as valuable.