KD tore his non dominant leg Achilles which is his right Achilles. Players who are right handed often jump off their left leg which is not the leg KD tore his Achilles on. Dominique Wilkins had the same injury on his non dominant leg Achilles and he averaged 30 the next year.
KD has the longest rehab time from an NBA player who tore their Achilles. That time would be 560 days by the time he plays again December 22nd. That is by far the longest rehab time.