Disclaimer: I hope Kevin Durant stays healthy this year.
However... if he re-injures his foot again, it would likely result in a 4th surgery for that same body part. Knowing the history of how big-men have been so sensitive to foot injures (i.e. Yao, Bill Walton, Embiid), would you be willing to trade the Brooklyn pick for a re-injured Kevin Durant?
I would still do the trade, but I think it's worth a discussion.