All Indian cricketers have been confined to their homes since March.
Karthik's Tamil Nadu and India teammate, off-spinner Ravichandran Ashwin, also had earlier confirmed he started off okay with regards to this phase, but has now started feeling "itchy" and desperate to return to on-field action.
The central government was forced to announce a nationwide lockdown near the end of March to try and stem the spread of Coronavirus. Since then, all cricketers are confined to their four walls, although restrictions have been lifted gradually.
"In the lockdown, initially, I was happy to train, I was happy to be at home doing stuff, but it got (extended) 2, then 3 and 4 weeks, I was kind of disoriented. I don't know when my next cricket game is, what am I training for, it was boring at times," Karthik said on Star Sports' show 'Cricket Connected'.
Karthik has drawn inspiration from his wife and international squash player, Dipika Pallikal, who is also dealing with the pandemic.
"So, then I see this person who is playing an individual sport, go and push yourself everyday you know. Same situation, she doesn't know when the next tournament is. I have a feeling cricket will probably start before squash, but she's still training like this without any game around the corner," he said.
Karthik, also the Kolkata Knight Riders (KKR) captain in the IPL, meanwhile, said his team will dedicate the trophy if they win the league's 13th edition post this pandemic to the people of West Bengal who have faced twin crisis borne out of COVID-19 and Cyclone Amphan.
"We are definitely emotionally very attached to Kolkata," he said. "They are really proud of us. The state has gone through a lot in the last couple of months. So I think winning the IPL, is the least we can do for the state."
Speculations have been rife that the IPL 2020 can replace the scheduled T20 World Cup if the ICC decides to postpone it from the October-November slot.
If played in Indian winter, the dew will pose a massive challenge for all IPL teams. But Karthik said his team will be prepared for that eventuality.
"We don't know yet. Even if the IPL happens, is it going to be like the home and away basis or it's going to be held in one centre. There are a lot of variables to this. But even when we play in the month of April-May, I can tell you that Kolkata has a strong amount of dew so teams like to chase."
"It might be a little more (in October) but one of the things that we will do in practice is to make sure that we do our best and practice with the wet ball as well," he concluded.
(Inputs from PTI)