Can Boston Celtics defense stay elite without Kristaps Porzingis?

We continue our look at Celtics camp questions by looking at the defensive side of things. Can the Celtics defense stay at an elite level without Porzingis to start the season? How far can it drop and Boston still be OK? John Karalis of Boston Sports Journal and Tom Westerholm dig into it and look at how the defense might look different, and why the offense might just be good enough for it not to matter a whole lot.