If Plan A is signing a major free agent and Plan B is trading for a star, what should Plan C be? There are a bunch of draft picks to use but they may get consolidated via trade so that there are roster spots that might be open.
With 2017 shaping up to be a good free agent crop, one idea is to sign a veteran free agent to a contract similar to that of Amir Johnson, unguaranteed beyond the first year with more money to compensate the player for giving the team more payroll flexibility.
One obvious target is Zaza Pachulia. He's too old to hope for a long-term deal. He is a willing passer, capable rebounder, and solid defender who is good against the pick and roll and protects the paint, even if he is not a shot blocker. It's no surprise that Milwaukee looked worse after losing him. In the absence of acquiring a star, I would be pleased with signing Pachulia to such a deal.
Who else is a potential target for this sort of contract? I'd say it's the sort of deal you might offer the Celtics' own free agents such as Evan Turner if no clear upgrade exists.