However, the BCCI press release doesn't mention the specific nature of the offence.
"Karthik admitted to the Level 1 offence under Article 2.3 of the IPL Code of Conduct and accepted the sanction. For Level 1 breaches of the Code of Conduct, the Match Referee’s decision is final and binding," the release stated.
RCB defeated debutants Lucknow Super Giants by 14 runs in the IPL Eliminator on Wednesday.
As far as Qualifier 2 is concerned, Dinesh Karthik will again have to be at his best if RCB want to qualify for the playoffs.
RCB vs RR Match Preview
Having sneaked into the playoffs, RCB are on a roll and a tight win over Lucknow in the Eliminator has fuelled expectations for a long-awaited trophy.
They take on Rajasthan, a team which has all bases covered but still came up short against Gujarat in Qualifier 1.
The IPL caravan moves to Ahmedabad after a couple of high-scoring games in Kolkata.
It has been a quick turnaround for RCB, but they won't mind that as they look to ride the momentum.
"The best thing is that we have one day, and we play again. Cannot wait to be in Ahmedabad and take the field again. We are so excited and happy with how things have gone.
Hopefully, two more games and we all can celebrate," star RCB batter Virat Kohli told the IPL website after the win over LSG.
Rajat Patidar, who played the innings of his life on Wednesday, will be a man with supreme confidence in another high-pressure knockout fixture.
For someone who went unsold in the IPL auction and came into the RCB squad as a replacement player, it has been a career-changing season for him.
Both the high-profile openers, Kohli and Faf du Plessis, are big match players and will be itching to make an impact after low returns in the previous game.
Dinesh Karthik has managed to maintain consistency in a tough role and the team management would be also hoping for more runs in the back end of the innings from Glenn Maxwell.
The team is likely to stick to the winning combination.
While Wanindu Hasaranga has shown the courage even when he has been taken to the cleaners, Harshal Patel has been the go-to pacer in slog overs.
Mohammad Siraj returned for the LSG game and bowled well with the new ball. Josh Hazlewood enhanced his reputation as a death bowler with a match-deciding penultimate over and with the addition of a yorker in his armoury, has only become tougher to score off.
RCB bowlers will have to be on the top of their game against a formidable Rajasthan batting line up which relies heavily on Jos Buttler and skipper Sanju Samson. Both scored against Gujarat but , it did not prove to be enough.
Samson will be eager to convert his 30s and 40s into a substantial knock and lead from the front.
It remains to be seen how the bowlers come back after a forgettable outing.
R Ashwin had a rare off-day against Gujarat while Prasidh Krishna paid the price for bowling length balls to David Miller in the final over.
Rajasthan Royals: Sanju Samson (captain), Jos Buttler, Yashasvi Jaiswal, Ravichandran Ashwin, Trent Boult, Shimron Hetmyer, Devdutt Padikkal, Prasidh Krishna, Yuzvendra Chahal, Riyan Parag, KC Cariappa, Navdeep Saini, Obed McCoy, Anunay Singh, Kuldeep Sen, Karun Nair, Dhruv Jurel, Tejas Baroka, Kuldip Yadav, Shubham Garhwal, James Neesham, Nathan Coulter-Nile, Rassie van der Dussen, Daryl Mitchell, Corbin Bosch.
Royal Challengers Bangalore: Faf du Plessis (captain), Virat Kohli, Glenn Maxwell, Mohammed Siraj, Harshal Patel, Wanindu Hasaranga, Dinesh Karthik, Josh Hazlewood, Shahbaz Ahmed, Anuj Rawat, Akash Deep, Mahipal Lomror, Finn Allen, Sherfane Rutherford, Jason Behrendorff, Suyash Prabhudesai, Chama Milind, Aneeshwar Gautam, Karn Sharma, David Willey, Rajat Patidar and Siddharth Kaul