One of the key issues is that nearly every other team competing in the race has games in hand, with Boston being put in a tight spot. Addressing this, GM Don Sweeney conceded that the Bruins would likely be sellers at the NHL trade deadline.
The Bruins are, in fact, shopping him around, and if no extension is reached, it's all but guaranteed he'll be traded. Losing Frederic would sting, but it's better than watching him walk for nothing in free agency.