Ponting, who was initially named as MI captain for IPL 2013, stepped aside for Rohit Sharma due to poor form. Despite failing to make a contribution to the team on the field, Ponting is now making an impact on the franchise with his vast knowledge, according to Karthik.
"He (Ricky Ponting) is the biggest thing to have happened to Mumbai Indians," Karthik told iplt20.com on Wednesday (May 8).
"He has this aura about him and he brings in a lot of positive energy in the team. Some of the things that he says in team meetings and some of the points he brings to the fore is really hair-raising. People don't know about many things happen at the back-end but there's a lot that happens behind closed doors. He is the key reason for us to be so positive and motivated," Karthik added.
The wicketkeeper-batsman, who has been in fine batting for MI which earned him a recall to the Indian team for Champions Trophy, said his job became easier with the presence of big-hitters in the team.
"Yes, when you know there are some big hitting batsmen in the middle-order who can tonk the ball a mile, your role gets easier because you just try and get them on strike. When they are not around, you have the license to hit the big ones as well," he said.