Napoli are optimistic striker Arkadiusz Milik will only miss three months of action after rupturing the anterior cruciate ligament in his left knee.
The 22-year-old was forced off at half-time of Poland's 3-2 2018 World Cup qualifying win over Denmark on Saturday and the subsequent scan a day later revealed the severity of the problem.
He will have to contend with a lengthy spell on the sidelines, but Napoli's medical chief Alfonso De Nicola is hopeful that he could be back playing as early as January.
"The left knee of Milik is in perfect condition, beyond the damage to the ligament," he told Radio Kiss Kiss. "We expected to find further injuries.
"On the recovery time I want to be optimistic. It will be shorter than the timeframes initially announced as they were precautionary.
"We say [he will return] in three months, maybe three and a half, but we are hopeful that it will be even less."