Mumbai Indians found themselves in the middle of a major controversy during IPL 2026 after a concussion substitute decision involving Mitchell Santner sparked widespread debate.

The incident occurred during their clash with the Chennai Super Kings when Santner injured himself while taking a catch. The New Zealand all-rounder was seen clutching his shoulder and had to leave the field. Soon after, the Mumbai Indians brought in Shardul Thakur as a concussion substitute—a move that raised eyebrows.

Questions quickly followed. Under IPL rules, concussion substitutes are only permitted for head or neck injuries and must be backed by a proper medical assessment. In Santner’s case, the injury initially appeared to be related to his shoulder, with visuals later showing him icing it in the dugout. This led to doubts over whether the rule had been applied correctly, as well as whether Shardul qualified as a like-for-like replacement.

Mumbai Indians head coach Mahela Jayawardene addressed the issue after the match, insisting the decision was medically justified.

“He hit his head first and neck. Obviously, the shoulder as well,” Jayawardene said. “He went for a scan. Once he got back, he felt dizzy. So, he was lying down. Yes, the ice was there for the shoulder, but he felt he wasn’t stable. So, we took him for a scan.”

He added that the final call rested with match officials. “We requested (for a concussion substitute). Obviously, it is the match referee and the umpires’ discretion. They allowed Shardul,” he said. “Mitch will be disappointed that his batting prowess was matched to Shardul, but it is what it is. Hopefully, it’s not too bad.”

Despite the substitution, the Mumbai Indians failed to recover in the game, eventually suffering a heavy 103-run defeat.