Tasnim - The Iranian national football team and Esteghlal's defender Pejman Montazeri underwent shoulder surgery in Tehran’s Bahman Hospital.
Montazeri suffered a shoulder injury in practice last week.
He will be out of action for Esteghlal for at least two months.
The 33-year-old international defender joined Esteghlal on a two-year contract in late June.
Montazeri was a member of Team Melli in the 2014 FIFA World Cup and played full 90 minutes in all three matches against Nigeria, Argentina and Bosnia and Herzegovina but missed 2015 AFC Asian Cup due to injury.
Montazeri’s injury is a "big blow" for the Blues since they sit 15th in Iran Professional League after five weeks.