Haynes, who scored in Saturday's 4-2 win over Preston, has a hamstring injury and faces a race to be fit to face Dave Jones' men.
Costa Rica forward Alvaro Saborio and Scotland international David Clarkson will battle to replace Haynes if he does not make it, but manager Gary Johnson is unlikely to make any further changes.
His side secured just a second win in 12 games against Preston, with Johnson opting to alter his formation to incorporate Jamie McAllister and Ivan Sproule as wingers.
"A result like that definitely helps with confidence," said Johnson, whose side secured the replay with a 92nd-minute goal from Gavin Williams.
Cardiff are facing yet more injury problems.
Illness has swept through the camp of late and, although most players have now fully recovered, Solomon Taiwo is the latest player to be sent home feeling under the weather. But Mark Kennedy has recovered from the virus.
Captain Mark Hudson and fellow defenders Adam Matthews and Kevin McNaughton and midfielder Aaron Wildig all picked up knocks in Saturday's 1-1 draw at Scunthorpe and are struggling.
Gavin Rae continues to miss out due to his hamstring injury while striker Josh Magennis is a long-term absentee as he recovers from a broken fibula.
Joe Ledley will be available to make what could be his last appearance of the season before undergoing a double hip operation, with the Wales midfielder also able to play in Saturday's fourth-round clash against Leicester should the Bluebirds progress.
Jay Bothroyd (illness) and Chris Burke (rib) recovered to feature at Glanford Park and they are both in the frame once again, while Ross McCormack is also feeling 100% having been rested on the bench at the weekend and could start.