Obviously I love the deal, but just to point out to anyone who thinks Zeller is a potential solution to our starting center problem: he has a 8'8" standing reach. That's THE lowest number for a center prospect in the last 5 drafts, and 6th lowest for a PF prospect. He has the standing reach of an average NBA SF. He will simply never be a serviceable rim protector.
Can he crash the offensive boards, score efficiently in the pick-and-roll, and occasionally step out to hit the 18 footer? Absolutely, but if he's doing that as part of a championship winning Celtics team, it will be in limited minutes off the bench.
A note about measurements like standing reach: some players intentionally short arm their reach so it makes it look like they can jump higher, as their jump is just their vertical minus their reach. Not sure if that's what Zeller did or not, but the best number to look at when comparing players is max vert reach. He put up an 11' 6.5" number there, which is still below average, but not the worst ever, and better than Nicola Vucevic and Greg Monroe. No step vert reach also gets rid of this gaming of the combine -- there Zeller is below Vucevic but ahead of Monroe.
I'm not saying Zeller is amazing -- he's not. I'm just trying to provide context to his measurements.