Ya it was a back injury. Drozd in his second career became a rather tidy fighter but everything he was good at Usyk is better in addition to being bigger and faster. It would be a very very pleasing fight to watch though. I would have loved to see him and Briedis.
Sucks that Drozd was derailed by injury as he really started to put everything together. Usyk beats him but Drozd would give a good account of himself.