You pickup Kovalchuk now for a little extra over Zucc's salary and trade Zucc at the deadline (potentially bundled with a Spooner and pick) to move up in the draft, and the move is already paying dividends, not even taking into account the sway a guy like Kovalchuk has on some of the "unsure" assets in Russia.
And you sign him for three in the hopes he makes your team competitive, but if in that third year you're not you can absolutely trade him at the deadline, because I don't think anyone here disagrees that he will produce. Obviously not to the level he did before he left, but will still be top two lines on any team, as others have said.