Maybe I'm missing something, but why not cut Johnson? Only 40 d-men are owned in your league, so it won't be so devastating if someone grabs him, especially if they have to then wait out his injury. Plus, there will always be decent options on the WW with only 40 guys on rosters.
If that's not possible, then maybe Hossa would be the one to go. He's on the decline and not even part of Chicago's PP1 anymore.