Karthik faced only seven balls in the T20I series against Australia.
The Men in Blue have three T20Is left against South Africa at home ahead of the T20 World Cup 2022, slated to get underway on October 16.
India have been alternating between Karthik and Rishabh Pant in their playing XI. While Pant played most of the games in the Asia Cup 2022, Karthik was picked for all T20Is against Australia.
"I wanted both of these guys to have a number of games under their belt before the World Cup. When we went to the Asia Cup both of these guys were in the fray to play all games," Rohit said at the post-match press conference after India won the third T20I in Hyderabad by 6 wickets on September 25.
"But I just feel that Dinesh needs a little more game time. He hardly got to bat (this series). Just maybe three balls. So that's not enough time," he added.
Karthik faced only seven balls against Australia whereas Pant featured in the rain-curtailed second T20I but didn’t get a chance to bat.
"Pant also needs game time obviously. But looking at how this series was it was important for me to just stick to that consistent batting lineup."
For the South Africa T20I series, September 28 in Thiruvananthapuram, Rohit said Karthik and Pant's inclusion in the playing XI will depend upon the situation.
"I don't know what we're gonna do against South Africa. We just need to go and see their bowling, what sort of bowling lineup they'll play with, and who are the best guys for us who can handle that bowling lineup. It all depends on that.
"We want to be flexible in our batting. So if the situation or if the thing demands that we need a left-hander, we will bring in a left-hander if we need a right-hander, we will continue to do that.
"But we'll try and manage those guys pretty carefully. I do understand that they need game time before the World Cup but there are only 11 players you can play, unfortunately."
(With PTI inputs)