Well,
Eller is our 3rd line center or perhaps our left winger on our 2nd line.
He is important to our team as we hope he will perform again in the playoffs. Unless Bergevin gets a player that is young, not a rental, and signed for a few years he won't be traded.
If Bergevin wants to trade west I can see these players:
Mikael Boedker, left wing, Arizona (if ready to play after the surgery)
Dwight King, left wing, Los Angeles
Brandon Saad, left wing, Chicago (one can dream) or Andrew Shaw, Chicago, center
Ryan O'Reilly, center, Colorado
Eastern teams:
Mike Hoffman, left wing, Ottawa (good offense, but body too lean?)
Nazem Kadri, center, Toronto (less stong physically, but better offense, attitude?)
Jeff Skinner, left wing, Carolina (take a chance that he will rebound)
Josh Bailey, left wing, New York Islanders
Derek Stepan, center, New York Rangers
There are some options but honestly nothing amazing. Maybe a good prospect not yet playing in the NHL would give a better trade value.