Lee Tomlin in action for Cardiff
Ward was expected to join Millwall on transfer deadline day, but Cardiff have made a late move for the Northern Ireland international and proposed Tomlin in a swap deal.
Ward has found himself on the fringes of the Forest team this season, making only seven appearances off the bench in the current campaign.
Tomlin has found himself out of favour at Cardiff in recent weeks and he has only started five games in the Championship this season.
Bluebirds boss Neil Warnock is willing to let Tomlin move on if he can find a replacement and he is ready to take versatile forward Ward in a swap deal for Tomlin.
New Nottingham Forest boss Aitor Karanka is determined to strengthen his squad before the close of the transfer window after a difficult start to his tenure at the City Ground.
Karanka is a big admirer of Tomlin having worked with the attacker during his time in charge of Middlesbrough and is keen to be reunited with him.