Explained: Why Mumbai Indians replaced Mitchell Santner with Shardul Thakur as concussion sub despite a shoulder injury

Here's why Shardul Thakur was allowed to come in as the concussion substitute for Mitchell Santner.

The Mumbai Indians versus Chennai Super Kings (CSK) contest in the Indian Premier League (IPL) 2026 season was expected to be a cracking affair; however, the match at the Wankhede Stadium on Thursday turned out to be a one-sided affair as the five-time champions CSK registered a comprehensive 103-run win on the back of Sanju Samson's unbeaten century and Akeal Hosein's four-wicket haul. However, the biggest talking point was neither of these two performances, as all the chatter was about Shardul Thakur and how he was allowed to bat for the Mumbai Indians despite not being in the playing XI. He also didn't come in as the impact sub, as that role was fulfilled by Danish Malewar, coming in for Allah Ghazanfar.

Shardul Thakur came in as the concussion substitute for Mitchell Santner. (PTI)

Shardul walked out to bat as he was named the concussion sub for Mitchell Santner, who suffered an injury in the 17th over of CSK's batting innings. The New Zealand T20 captain injured his shoulder when he took the catch to dismiss Kartik Sharma and send him back to the hut. Speaking of Santner's catch, he had dived forward to complete a good low catch, and in the process, ended up injuring his shoulder. Mumbai Indians' owner Akash Ambani also sported a concerned look, and he checked up on Santner near the dugout.

However, later replays showed that Santner’s head hit the ground while attempting the catch. It is worth noting that Santner had bowled his quota of four overs by then, conceding 44 runs and picking one wicket. When this incident occurred, the Mumbai Indians had already used the impact player option, bringing in Malewar in place of Ghazanfar.

During the Mumbai Indians' batting innings, the cameras panned to Santner in the dressing room, who was wearing a sling to support his shoulder. Shardul, coming in as the concussion sub, didn't yield any sort of results for the hosts as the right-hander managed just six runs off 12 balls.

Mumbai Indians head coach Mahela Jayawardene was also asked about the decision to have Shardul as the concussion sub. Speaking to the reporters at the post-match press conference, the former Sri Lanka captain said, “Santner hit his head first, the neck and obviously, the shoulder as well. He then went for a scan. Once he got back, he was lying down. Yes, the ice was there for the shoulder, but he felt that he wasn't stable, so we took him for a scan in that situation.”

“We requested a concussion sub. It's at the match referee and the umpires' discretion. They allowed Shardul Thakur. It is what it is. But hopefully, Santner's injury isn't too bad. Once he's back, we'll have a look at it,” he added.

What do the official rules say?

According to the official rules, all teams must name their substitute players (for concussion subs) to the match referee before the start of the match, as follows: one wicketkeeper, one batter, one all-rounder, one seamer, and one spinner. If the replacement player also gets concussed and needs to be replaced, the match referee can consider a player from outside the five nominations, in accordance with the existing like-for-like protocol.

CSK jump to the fifth spot

With the thumping win over the Mumbai Indians on Thursday, CSK jumped to the fifth spot in the points table with a total of 6 points in 7games. Samson was adjudged as Player of the Match for his unbeaten 101-run knock.

In the game between the Mumbai Indians and CSK, the former won the toss and opted to bowl first. CSK then posted 207/6 in 20 overs, riding on Samson's century.

With the ball, Akeal Hosein turned out to be the game-changer for CSK as he returned with four wickets, while Noor Ahmed took two wickets. Jamie Overton, Anshul Kamboj, Mukesh Choudhary and Gurjapneet Singh took one wicket each as the Mumbai Indians folded up for 104.