The forward's pro day was initially canceled due to a strained hip, per Jonathan Givony of ESPN. He was reportedly suffering from back spasms Thursday.
While Porter believes he's healthy, teams want to evaluate him themselves with their own doctors, Adrian Wojnarowski of ESPN reported:
Medical question marks could lead to a draft-day slide for Porter, who missed the majority of his lone college basketball season at Missouri due to a back injury.
He ended up playing just three games during his freshman season, totaling 53 minutes on the court.
Porter is still loaded with upside and was considered the No. 2 overall prospect in the 2017 recruiting class by 247Sports. Even with injury question marks, Bleacher Report's Jonathan Wasserman lists him as the No. 9 player in the 2018 NBA draft.
Teams will want to make sure his injuries won't limit him going forward, but he likely won't fall too far in next Thursday's draft.