I think the return for Karlsson is going to be extremely underwhelming for Ottawa. Everyone knows he's leaving, especially after the Hoffman stuff. If it's not a sign and trade, they won't get anything back. Even if it is a sign and trade, there are questions about his health, and he'll want a ton of money, so the teams Ottawa can realistically send him to are what? maybe 3-6 teams?
My point is, what is the point of devaluing that even more by throwing in Bobby Ryan? They're clearly in full rebuild mode, and he's only got 3 years left. Just keep him and eat the cap space to get you to the cap floor while you rebuild.
By the way, what the hell happened to him? He just completely fell off a cliff around 25
https://www.hockey-reference.com/players/r/ryanbo01.html