The Manchester United defender has been struggling with a calf injury picked up in the semi-final, second leg at Arsenal earlier this month and did not make Sunday's Premier League trip to Hull as demanded by Sir Alex Ferguson.
He said:
"The injury is fine," he said. "I have been training and feel good. I am glad to be back."
That scenario does not appear likely, with Ferdinand insisting he would not risk the team by putting himself forward for selection if he was not 100%.
"I wouldn't do that," he said. "There is no way I will play if my fitness was detrimental to the team.
"Tomorrow is more about the team winning than me playing in a cup final.
"In any case, I have been working hard with the medical staff and training well. There are no problems. I am fine."
With Ferguson revealing no other injury concerns, he must wrestle overnight with a thorny selection dilemma.
United's defence picks itself, while Cristiano Ronaldo and Wayne Rooney also appear certain of their places.
Michael Carrick is expected to be involved as well along with veteran Ryan Giggs, leaving midfield duo Anderson and Park Ji-sung, who did not even get a place on the bench against Chelsea last year, to scrap it out with Carlos Tevez and Dimitar Berbatov for the remaining two slots.