This is just speculation that Carter Yakemchuk could be traded for a defender or top tier forward, but Yakemchuk for an extended Rasmus Andersson would be a decent trade for both teams:
Sportsnet: Ottawa Senators mailbag
I could see that team doing something like this if Andersson is open to extending there as they are desperate to become a valid contender in the next couple years to keep Tkachuk long term.