To the best of my knowledge, Elias Lindholm will be the best center available this offseason in free agency. He is better than anyone on the Bruins' roster at present, and with the cap-space I've heard will be available, the Bruins MUST sign him.
Otherwise, a trade must be made. Number 1 centers are expensive, and it will absolutely cost the Bruins dearly. Ullmark will assuredly be part of any deal the Bruins make. The question is; who else? You have to give up something to get something. For a LEGIT superstar center, or the draft pick necessary to get one, it will likely be Ullmark + McAvoy + ???.
Those are the Bruins' options. I like to think Sweeney knows this, but who really knows what goes on down there on Causeway Street. I've often wondered what Cam Neely and Don Sweeney actually do all day... Or Chuckie Jacobs, for that matter.