Tabb was forced off at the interval of City's 2-0 win against Norwich on Saturday with a knock to his knee caused by a reckless challenge by Dejan Stefanovic.
Jay Tabb
Gray was replaced twenty minutes from time as a precaution with a knock which what Chris Coleman described as a 'nicked his groin'.
Julian Gray in pre-season action
Kevin Thornton or Robbie Simpson could replace Tabb whilst Leon McKenzie, who came off the bench to score is expected to replace Jules Gray.
Both Clinton Morrison and Freddie Eastwood are expected to start. Chris Coleman described the pair as 'nowhere near match fit' but added that would come