Wales are said to have concerns about skipper Aaron Ramsey for their Euro 2024 play-off.
The European nation are set to take on Finland to see if they can eventually earn a spot at the summer showpiece event.
However, Cardiff boss Erol Bulut admits Ramsey is not fully fit at the moment.
Bulut said: For Tuesday it will be difficult, I think around one week.
"He got injured, he has a strain on his calf.
"Also Perry Ng was injured on his hips. That's why they didn't play.
"For Tuesday, Aaron, it will be difficult. I think it will be a short time, around one week.
"We saw in the last game, at West Brom, when he came in, it was a different game from how we started.
"We got a few chances to score and make it 1-1.
"It would be great to have him, but if a player is injured, I cannot change it."