If Rondo is healthy and is available for 44 games, coming back for the first home game after the West Coast trip against Houston January 13th, the Cs probably make the playoffs. The 8th seed in the East will need only 35 wins, the Cs have 11 already, with 57 to play.
If they go 5-8 without Rondo, they'd need only 19 wins in 44 games with Rondo, playing tanking teams half the time at the tail end of the season. If Boston is going to tank, they need to go into a tailspin right now. From what we've seen so far, they're not going to tank.
At a minimum, Boston wins 38 games and gets the 7th seed, and gets knocked out in five games in the first round against either the Heat or Pacers. Rondo is a winner, and he's going to do a great job leading these young guys.