The 30-year-old actor was performing a daring stunt when a ligament in his right knee tore five days ago.
He says the slippery ground where he had to perform the stunts caused him the injury.
"We practiced a lot and I could do the stunt properly every time, but unfortunately on the day of the shoot it was pouring and the ground was slippery. That caused the injury. I am glad that we could still finish the scene as planned," Sushant said in a statement.
The extent of Sushant's injury has resulted in the doctors advising him to refrain from running or indulging in any kind of strenuous workout for a month.