If you want to trade Bogi away and then offer him a contract, you have to have cap space. We won't have $15M of cap space. We'll probably have about $9M.
Interesting that you know my assumptions when I haven't stated them.
There is a big difference between having a player's RFA rights and trying to sign another team's RFA. If we trade Bogi, and then want him back as another team's RFA, then we probably have to find a way to clear the cap space to offer $18-$20M, because otherwise his own team (who, in your scenario, has given up a first-round pick for him and obviously wants him around) will just match. We've got to blow them out of the water to get him. On the other hand, if WE hold the RFA rights, we don't have to offer anything. We wait for another team's contract offer to come in. If they offer $20M, we let him go. If they offer $12M, we match and we don't have to maneuver around the cap to do so.