It is hoped that both players will be available for the FA Cup semi-final on Sunday against West Ham at Villa Park.
With Chris Riggott suspended for the trip to Romania it leaves a selection problem for Steve McClaren in the centre of defence. Ugo Ehiogu will captain the side with either David Wheater or Matthew Bates alongside.
Another option is to play Franck Queudrue in the centre and play Andrew Davies at fullback.
Upfront the disappointment of missing Viduka is boosted by the inclusion of Malcolm Christie who could play some part in the procedings.
The squad that has travelled to Bucharest is:
Schwarzer, Jones, Queudrue, Ehiogu, Southgate, Boateng, Hasselbaink, Rochemback, Christie, Parlour, Doriva, Maccarone, Downing, Yakubu, Parnaby, Morrison, Bates, Wheater, Taylor, Johnson