For me, unless he can prove he is 110%, I would pass.
Even if he becomes the next Durant and we pass on him because of the concerns about his back, I could live with that missed opportunity.
But, if we draft him and he winds up having an injury plagued career, then the franchise is screwed for years.
Can we really take that type of risks in our situation, with no 2019 pick and other high quality prospects available like Doncic and Bagley, et al. at #2?
Personally, I don't think it's worth the risk since MPJ doesn't seem to want to go through the drills to prove his back is 100% healthy.