The former Ajax Cape Town man picked up a left knee tendon injury in May, which was diagnosed as tendinosis.
"I've been out of action for about four months because I got the injury back in May and then had a good rest during the off season," Claasen told KickOff.com.
"So while I had good time to rest, I am now itching to play again."
The man from Klerksdorp believes that getting back to full match fitness is his immediate challenge, but he believes the support from his club will make it an easier road back.
"I feel good, but I am currently not match fit. Look, I have rested well and now I have had enough of sitting around. I have spent a lot of time in the gym and the club have been very helpful in this process," he says.
Regarding his future in the South African national team, he said: "It would be a great opportunity and honour just to be part of our team at Afcon 2013. I hope and pray that things do work out and I hope we can make the nation proud."