Literally anyone, at 1.5m or less. Dubas is a pretty good dumpster diver and has been shrewd at picking up depth pieces like Giordano, Lyubushkin, and Bogosian on cheap deals. We would only need 16 points, PP2, and 3rd pairing minutes for 51 games replaced, there are a whole lot of players who can do that and it comes cheap. We're talking about the #7 here, a replacement here is as easy as it gets.
And to be honest, you're having one of those "Leafs are the centre of the universe" moments. We just went out in the first round again and don't even have a goalie for next year, who's got our #7D at the top of their hit list? And then on top of that, GM's barely have enough cap space as it stands, they're not lining up for a chance to commit 3m to a 3rd pairing PP specialist who doesn't think he can even beat out Justin Holl for minutes. There are RFA's with Sandin's upside every single year and they never get offer sheeted.