A hamstring injury kept the Villa captain out of Saturday's 2-0 defeat to West Ham, after which manager Paul Lambert criticised his side's defensive display.
However, the Scot has revealed he could be boosted by the return of the Dutchman for the trip to south Wales.
"I think there might be a chance," he is quoted as saying by the Birmingham Mail. "I'll have to see how he feels.
"You cannot risk it. He's got to feel himself if he can play and if he's comfortable and thinks he can play then you have to look at it. Ron being out is a bitter blow.
"It was touch-and-go whether he could play on Saturday."
Vlaar has started each of Villa's seven Premier League victories this season, while the Villa Park outfit have lost five of six matches in which he has not played.
"Whether Ron is fit for Cardiff I'll see, but it affects most things because of the balance," he continued. "With two left-footers playing as your centre-halves, it's not ideal.
"The two boys (Saturday's centre-back pairing of Ciaran Clark and Nathan Baker) have been doing great every time I've asked them to go and do it and if they make a mistake it's an honest mistake, but Ron being there it gives you that experience.
"He gives you the balance. That's the big thing. He's been round the block so he knows what the game entails. It was a blow for him not to play.
"It took him a little bit to adjust to life in the Premier League but this year he's been very good."
Villa sit 12th in the Premier League, four points clear of the relegation zone and six ahead of 19th-placed Cardiff.
