His current contract has two years left to run and talks are planned in the near future on an extension.
Vassell told the Birmingham Mail: "Things were going to happen on a new contract before the World Cup but we decided to leave it.
"Hopefully, if I can start performing again, something will happen soon because I've always said that I don't want to leave Villa and that remains the case.
"As for my fitness I should be fine for Sunday. I've just been doing some light stuff but it's precautionary. I didn't want to make it worse by training hard.
"I struggled with blisters when I was away at the World Cup but it's not really an ongoing problem. It's just one of those awkward little things.
"I don't know what the cause is and it doesn't happen that often but I'm trying to get them treated properly so it doesn't happen again."
Vassell added: "I was really pleased with last season and how I did and to go to the World Cup was superb. But that's behind me now and the good players keep doing it season after season.
"I've got another big season ahead of me and I want to reproduce some of last season's form. I also want to be more consistent."