India captain Rohit Sharma was coy Tuesday on how his team will line up for the Boxing Day Test against Australia, with the option of a second spinner on the table.

Temperatures are forecast to reach 40 degrees Celsius (104 Fahrenheit) on Thursday, and the Melbourne Cricket Ground curator said during the week he expected the pitch to offer plenty for the fast bowlers.

But Rohit left the door open to a second spinner.

"Whatever we have to do to make the best possible XI in these conditions, we will do that -- whether that is playing an extra spinner or not," he said.

With off-spinning allrounder Ravichandran Ashwin announcing his immediate retirement from international cricket after the third Test in Brisbane, Ravindra Jadeja is expected to keep his place.

Washington Sundar is the other spin option.

India has been carried this series by pace spearhead Jasprit Bumrah, who has tormented Australia almost single-handedly, with the other quicks not offering as much menace.

Speedster Akash Deep replaced the underperforming Harshit Rana in Brisbane and is set to play again along with Mohammed Siraj and Nitish Kumar Reddy should the second spin option not be taken.

Despite their lacklustre performance, Rohit defended the pace attack.

"When you talk about our bowling unit, I have enough faith in all our bowlers to get the job done," he said.

"Anyone can have tough games, tough series. But it doesn't mean they are not good enough to perform at this level.

"It happened that in these two or three games; they've not been able to get those big numbers, but that's okay, it happens. I have enough confidence and faith in them."

Rohit himself is under pressure.

After missing the first Test in Perth for the birth of his second child, he came in at six in Adelaide and Brisbane instead of opening to allow Yashasvi Jaiswal and KL Rahul to remain at the top of the order.

There has been mounting speculation that he could again start as opener in Melbourne, but brushed off questions about the likelihood.

"Let's not worry about that. I think who bats where is something that we need to figure out within ourselves," he said.

"It's not a thing I should be discussing at every press conference, where I'll be batting.

"Whatever it takes for our team to look good or gives us the best chance to succeed, we'll try and do that."

The two sides head into the match tied at 1-1 in the five-match series after India won by 295 runs in Perth before being crushed by 10 wickets at Adelaide.

The hosts were on top at the third Test in Brisbane, but persistent rain ruined the game and it ended in a draw.