As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER LANDING IN MMPR, WHILE PERFORMING THE WALK AROUND INSPECTION, THE CAPTAIN NOTICED A SECTION OF THE TREAD MISSING ON THE NR 1 MAIN TIRE. NO OTHER DAMAGE WAS REPORTED BUT THE TREAD SEPARATION. THE CAUSE OF THE TREAD SEPARATION COULD NOT BE DETERMINED. MECHANIC TO REPLACED THE BAD TIRE.