Russell Slade had said on the weekend that the sending off was valid.
"Should we have been down to 10 men? Yes. Should it have been a penalty? No," said Slade.
But after seeing the incident the club must feel that Marshall was unfortunate to be sent off.
Cardiff City are appealing over the red card awarded to captain David Marshall in Saturday’s 2-1 defeat at Rotherham
— BBC Wales Sport (@BBCWalesSport) September 21, 2015
