KL Rahul has been ruled out with injury, denting India's stock of backup batsmen.

David Warner is set for a comeback and Will Pucovski has been given the all clear, meanwhile, in potential boosts to Australia’s struggling top order.

With a series lead on the line at the Sydney Cricket Ground, there’ll be changes in the personnel when the third test starts Thursday.

Australia's Steve Smith walks from the field after he was dismissed during play on day three of the second cricket test between India and Australia at the Melbourne Cricket Ground, Melbourne, Australia, Monday, Dec. 28, 2020. (AP PhotoAsanka Brendon Ratnayake)

Australia's Steve Smith walks from the field after he was dismissed during play on day three of the second cricket test between India and Australia at the Melbourne Cricket Ground, Melbourne, Australia, Monday, Dec. 28, 2020. (AP PhotoAsanka Brendon Ratnayake)

The Board of Control for Cricket in India on Tuesday said Rahul had sprained his left wrist during batting practice on the weekend and would return to the National Cricket Academy in Bengaluru for rehabilitation on the injury.

Rahul hasn't played a test match since 2019, but was factoring in calculations for a return with the series tied 1-1 and two matches remaining. Rohit Sharma seems set to make his return from injury, with the only doubt over where.

With Mayank Agarwal tallying just 31 runs in four innings this season, it could be a straight swap at the top.

India's Jasprit Bumrah, second left, is congratulated by teammates after dismissing Australia's Steve Smith during play on day three of the second cricket test between India and Australia at the Melbourne Cricket Ground, Melbourne, Australia, Monday, Dec. 28, 2020. (AP PhotoAsanka Brendon Ratnayake)

India's Jasprit Bumrah, second left, is congratulated by teammates after dismissing Australia's Steve Smith during play on day three of the second cricket test between India and Australia at the Melbourne Cricket Ground, Melbourne, Australia, Monday, Dec. 28, 2020. (AP PhotoAsanka Brendon Ratnayake)

India's batting depth is being tested. Skipper Virat Kohli played in the first test, which Australia won by eight wickets, before returning home to be with his wife, who is expecting the couple's first child this month.

Stand-in captain Ajinkya Rahane posted a century that was instrumental in guiding India to an eight-wicket win in the second test at Melbourne last week.

Both teams are in Sydney, weighing up the best formulations for starting XIs on a wicket that traditionally takes spin.

Australia coach Justin Langer indicated Warner would return following almost six weeks on the sidelines with a groin injury, saying the veteran opener was “very, very, very likely to play" on his home ground.

An independent neurologist gave 22-year-old Pucovski clearance from a concussion sustained in a tour game, an assessment that put the young opener into the frame for a test debut.

Both openers went through batting practice on Tuesday, along with former skipper Steve Smith who is struggling for runs in this series. Joe Burns was cut from the Australia squad after the second test, leaving a vacancy in the opening pair, and makeshift opener Matt Wade could easily return to the middle-order to create another spot.

“All the concussion protocols ... have been passed. He’s been cleared and that would be very heartening for him," Langer said of Pucovski. “There’s no reason why Will can’t be selected now. It’s just working out the balance of our team, where we’re at in the series ... we weigh up whether this test match is right, or the next test match is right.”

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