Ravichandran Ashwin's departure from the ongoing third Test in Rajkot has left India with 10 players. Ashwin pulled out of the Test late on Friday after his mother fell ill in Chennai. BCCI confirmed the development in an official release, while its vice-president Rajeev Shukla gave further details.
The 37-year-old had a memorable outing on Day 2 of the Test. He scored crucial 37 runs off 89 balls, before breaking an 89-run opening partnership between Zak Crawley and Ben Duckett by dismissing the former, and becoming the ninth batter to pick 500 Test wickets.

"The BCCI extends its heartfelt support to the champion cricketer and his family. The health and well-being of the players and their loved ones are of utmost importance. The Board requests respect for the privacy of Ashwin and his family as they navigate through this challenging time," the BCCI release said.
"The Board and the team will continue to provide any necessary assistance to Ashwin and will keep the lines of communication open to offer support as needed. Team India appreciates the understanding and empathy of the fans and media during this sensitive period," it added.
BCCI vice-president Rajeev Shukla gave further details, and revealed that the off-spinner had to rush back home in Chennai to be with his mother who wasn't well.
India can get a substitute fielder on the field after approval from the umpires, however, he will not be allowed to bowl or bat. The substitute fielder can also keep wickets but after the permission from umpires. Here is what the law says.
According to Marylebone Cricket Club (MCC) - the guardian of the Laws of the game, umpires can allow a substitute fielder if they are satisfied that a player has been injured or become ill during the contest. As per MCC's rule No. 24.1.1.2, a team can have a substitute fielder for a 'wholly acceptable reason’. A substitute cannot bowl or act as a captain but the player can be a wicket-keeper only with the consent of the umpires
A replacement player is allowed only in the case of concussion injury. The concussion substitutes are allowed to take part in the match as a regular player. But no substitute fielders are allowed to bat or ball. Even if Ashwin was injured in some other manner and ruled out of the match, a player replacing him would not have been allowed to bowl or bat.
Can Ben Stokes allow India a like-for-like replacement?
England captain Ben Stokes can allow a like-for-like substitution on humanitarian grounds under exceptional circumstances. The England team has played with a different ideology under Stokes and head coach Brendon McCullum, and it should come as no surprise if someone like Washington Sundar for Axar Partel take the field for India, and is allowed to bat and bowl in place of Ashwin.