Jadeja was replaced by Chahal at the end of the India innings, right after he had bludgeoned a 23-ball 44, helping India recover from 92-5 to 161-7. Off the second delivery of the 20th over, Jadeja, in an attempt to pull Mitchell Starc, top-edged a delivery into his helmet. The ball lobbed to square leg, where Moises Henriques made a tumbling effort, but couldn’t latch on.

Despite the blow, Jadeja kept batting, hitting back-to-back fours off the fourth and fifth delivery and ending with 22 runs off his last 11 deliveries. However, it later emerged that he had been replaced by a ‘like-for-like’ option in Chahal for the second innings: a BCCI update mentioned that Jadeja was ‘currently being assessed by the medical staff’.

UPDATE: Ravindra Jadeja was hit on the helmet in the final over of the first innings of the first T20I.

Yuzvendra Chahal will take the field in the 2nd innings as a concussion substitute. Jadeja is currently being assessed by the BCCI Medical Team. #TeamIndia #AUSvIND pic.twitter.com/tdzZrHpA1H

— BCCI (@BCCI) December 4, 2020

The timing of the decision led to speculation: many wondered if the decision to replace Jadeja was an unfair advantage, as he was already struggling with an apparent hamstring injury in the first innings, and had been replaced by a specialist bowler. After the third ball of the 18th over, Jadeja was seen holding his right hamstring, and was attended to by the physiotherapist.

In the innings break, Justin Langer, the Australia head coach, was seen having a heated discussion with match referee David Boon by the side of the ground, with skipper Aaron Finch, padded up, quietly hearing the discussion.

To add to the drama, Yuzvendra Chahal, who was left out of the playing XI, and bowled a fantastic spell, picking up 3-25 from his four overs. And as expected, Twitter was filled with comments surrounding the two injuries to Jadeja, and whether India conveniently used the option to substitute.

BREAKING: Ravi Jadeja has been subbed out of the game with concussion meaning he can be replaced in this innings. He had copped a knock to helmet but batted on… and picked up with a late hamstring problem. Would suspect that's what the Langer and Boon blow up is about

— Ben Horne (@BenHorne8) December 4, 2020

Smart move from Team India to use the 'concussion substitute' rule to get Chahal on and bowl. The injury that clearly Jadeja was struggling with was the hamstring but then Chahal can't bowl.

Justin 'I go by the books' Langer is not happy about it. #AUSvIND

— Vinod Ramnath (@NaanumEngineer) December 4, 2020

Was Jadeja even checked after being hit on the head? Don't remember seeing it. He had pulled his hamstring and the physio was out there for that. https://t.co/cUr2NvbqwI

— Rohit Sankar (@imRohit_SN) December 4, 2020

Jadeja must be the first person in the world to get concussion from tweaking a hamstring #AUSvsIND https://t.co/AUKOERAPMF

— Adam Carey (@Adz176378) December 4, 2020

Was Langer’s anger justified? 🤔

The Aussie coach was clearly annoyed when he learnt that India had swapped Jadeja out for a concussion sub.

Jadeja was hit in the helmet at one point, but continued on. Appearing to also suffer a hamstring injury.

📸: @FOXSportsAUS #INDvAUS pic.twitter.com/V1wyx6s3b3

— ABC SPORT (@abcsport) December 4, 2020

I don't get the point. No doctor/physio came to check on Jadeja when he was hit on his head. But after he pulls a hamstring, suddenly he has a concussion? Isn't it protocol to check for a concussion immediately? Looks like India made use of a loophole. #AUSvIND

— Shams Rahman (@shamsrahman1805) December 4, 2020

However, as commentator Harsha Bhogle pointed out, the concussion could have been a delayed one, when the symptoms show up only after a while.

The only thing we need to be careful about before passing judgement on the concussion substitute episode was whether there was delayed concussion; whether he showed symptoms after going back to the dressing room. We don't yet know the answer to that. At the time, didn't look bad

— Harsha Bhogle (@bhogleharsha) December 4, 2020