Yes he can be sold with a fractured collarbone. The only reason he could fail a medical because of it are:
-If he's on painkillers which clash with the contrastfluid for the several tests he needs to do or the blood check, it's extremely rare for someone to have medication like this for an extended period of time after a fractured bone.
-The doctors don't trust that it will heal properly (very unlikely but clubs can be put off by it)
-If Hernandez has a history of trouble with his lymfenodes, especially around his neck. His medical record won't be made public but there's no reason to assume he has problems. The reason he could fail the medical because of this is because nuclear imaging devices pick up 'hotspots'. They are areas with loads of activity on cellular level, that can be a fractured bone or a different more serious abnormality. By doing a CT scan and checking his blood it can be confirmed it's only the fracture in his bone and nothing serious that shows up under the gamma camera.
As long as he's in good health otherwise he can pass a medical and be transferred. Ofcourse he will be less desireable as he will need to recover from it, but a medical shouldn't be a problem.