If I were a GM, I would pick Porter, Oladipo, McLemore and Bennett before I would pick either Noel or Len.  Why?  Because there is a clear history of big men with previous ankle/knee injuries that have been complete draft flops.  That coupled with I don't think that either Noel or Len are that talented to begin with.  Neither have impressive stats.  They represent potential.  I would draft more proven players first.  In a strong draft, these guys might not go until later in the lottery, Len even higher.  

Acording to ProBasketball Talk:  "Alex Len put up nice but not thrilling stats at Maryland last season — 11.9 points a game on 53.4 percent shooting, with 7.8 rebounds a game. He’s seen as talented but raw. After the season he had surgery on a stress fracture in his ankle, and there are concerns his health issues could be chronic."

and we all know about Noel's unsettleing serious knee injury. 

I hope more teams pick the big men center projects on the board before #16, which will leave the Celtics with better players to choose from.  We already have our big man project in Melo, who is as good or better than the rest.