"We didn't get an early date and Deepak will be operated Sep 20 in Kolkata by Anant Joshi," AIFF general secretary Alberto Colaco told IANS Friday.
The Mohun Bagan defender flew Thursday night to Mumbai accompanied by an AIFF official and met Joshi Friday.
The doctor advised an operation on the player's inured left knee, on which he suffered a muscle tear Monday during India's 1-0 win over Bangladesh in the ongoing Nehru Cup international football tournament.
Mondal was immediately rushed for an x-ray after the match. After an MRI scan Tuesday, it was revealed that the defender had suffered a muscle tear and fluid accumulation in his knee.
Mondal has been ruled out of the Nehru Cup and is doubtful for the Federation Cup in Ludhiana next month.
He had to undergo surgery two years ago on his right knee. Joshi was the surgeon then as well.
"Immediately after the impact, I felt there was a problem," Mondal had said the day he was injured.
His absence from the team is a big blow as the seasoned stopper is considered the backbone of the Indian defence.