The Portuguese international claimed he was ready to face Leeds on Saturday after recovering from shoulder surgery but Sir Bobby wasn’t fully convinced.
"I am fit enough to play right now," said Viana.
"But it is the manager's decision alone whether I do or not.
"I trained normally with the reserves early in the week and have spoken with Mr Robson, but he did not tell me when I might be playing in the first team again.
"He is in charge and I respect his judgement."
Viana is now likely to make his return as a substitute against Bayer Leverkusen or in the reserve game against Everton on Thursday.
He is the most likely man to replace the suspended Laurent Robert against Chelsea next Saturday, but if he is not fully fit Sir Bobby may consider Olivier Bernard or Clarence Acuna for the role.