Thomas was at the Millennium Stadium to watch the Wales squad go through their final paces before tackling France in the Six Nations - and vowed to be back among them again next season.
"I am going to play again. The doctors have given myself and my family confidence I can play again fully," said British & Irish Lion Thomas.
"My concern was that my family are okay with me playing. They have met the doctor with me and they realise rugby is as much a part of me as anything else. They know I want to get back playing and they support me.
"They will be behind me 100 per cent when I play because the doctor has given me the confidence I will be fine."
Caretaker coach Scott Johnson insists Thomas, who has won 88 caps, still has a major role to play within the Wales squad and backed his full-back to return as good as ever next season.
"People forget Gareth Thomas is captain of this team and it is just unfortunate circumstances that demand he is not with the team on the playing field," said Johnson.
"Wherever Gareth can be with the team, the intention is to have him around.
"And if he is right to go medically, I am sure Gareth Thomas will continue to play rugby. From what I am getting from the medical profession and Gareth himself he is okay in that perspective.
"Gareth won't retire from anything until he is not selected. But I see him as the greatest 15 in the world and I think he has still got plenty in him."
France may not have looked the dangerous attacking force that lit up the autumn international programme, but Johnson is wary nonetheless.
"They have the ability to threaten sides the most in the Six Nations," said Johnson.
"They haven't functioned right through a game this year but they are notorious for that. I am just hoping there is more bad than good on Saturday.
"France need to win and we want to win and that should make for an exciting spectacle."