The Costa Rica international was expected to play some part in Tuesday's Capital One Cup third round tie with Everton after missing the game against Chelsea with an ankle injury.
The 28-year-old picked up the problem in the previous Premier League game with West Brom but is now poised to make his return against the Bluebirds on Saturday.
Jol said he didn't want to risk Ruiz in the cup tie with Everton after earmarking the clash with Cardiff as a chance for the Cottagers to record their first win since the opening day of the season.
"It was a risk to involve him, that's why I played Kasami," he said.
Jol has also said he is likely to recall Kieran Richardson and Aaron Hughes to his squad for Saturday's game, Hughes having missed the last three games with a groin injury.