Greening at 2.65 is a tough sell but let's stop acting like the Sens are the only team with overpaid players and that Greening is overpaid by several millions a year...
For example, package Greening and Gryba (3.85 per season but for TWO roster spots, 3 years for Greening and 2 years for Gryba) and get only one player back at something like 3.0-4.0, for example Chris Kelly (3.0 x 2) (not saying that would happen because the Bruins are up against the cap)
Gryba is a cheap serviceable 6th/7th D-man, it doesn't look pretty on the ice at times but he has very decent defensive stats and only makes 1.2 a year. Thing is Ottawa has Borowiecki, Phillips, Claesson and many more who play or could play that shutdown bottom-pair role. Gryba is a RD but we have Alex Grant and Chris Wideman in Bingo who could bring another dimension to the team. I think Wideman is NHL ready and wouldn't mind having him there as a stop gap.
There's so many options and a guy like Gryba is certainly moveable if he fits a need (physical shutdown 6th/7th Dman who is safe in his own zone, despite how he looks at times), Greening it would depend (you can retain salary, you can give a mid-round pick attached to him or get a player NOT NEEDED by the other team with a bigger salary...).