I'm hoping it is like 2008 and we get to see our 8-12 finishing a lot of games.
But for the close games, I don't think there is going to be a set lineup. It should depend on the matchups, who is hot, are we protecting a lead or trying to take one, etc.
We know Rondo, Pierce, and KG will definitely be out there. Green would be my next guess. The 5th player could be a bunch of guys, which to me is a great problem to have.