A lively wicket has been prepared to benefit the South African pace bowlers but du Plessis said he was taking a gamble that it would be initially softer and slower on the opening day and then quicken up as it dried out later in the day.
"It is tricky one to call," he said.
South Africa decided to play with four seamers, which means a return to the test arena of Dale Steyn.
The 34-year-old, five wickets from becoming South Africa’s highest test wicket-taker, has been out for over a year with a shoulder injury.
It means Temba Bavuma has to sit out as the home side sacrificed a batsman in the first match of the three-test series. India captain Virat Kohli said he would have elected to bowl had he won the toss.
"We saw the South Africans warming up with their four seamers, so we wanted to get out on this green wicket and try and make some early inroads into their batting."
India handed a first test cap to bowler Jasprit Bumrah after his good form in recent One day Internationals. They picked three seamers and also have all-rounder Hardik Pandya with a lone specialist spinner in Ravichandran Ashwin.
Teams: South Africa: Faf du Plessis (captain), Hashim Amla, Quinton de Kock (wicketkeeper), AB de Villiers, Dean Elgar, Keshav Maharaj, Aiden Markram, Morne Morkel, Vernon Philander, Kagiso Rabada, Dale Steyn India: Virat Kohli (captain), Murali Vijay, Shikhar Dhawan, Cheteshwar Pujara, Rohit Sharma, Hardik Pandya, Ravichandran Ashwin, Wriddhiman Saha (wicketkeeper), Jasprit Bumrah, Mohammed Shami, Bhuvneshwar Kumar.
(Reporting by Mark Gleeson; Editing by Amlan Chakraborty)
