Defender Alex Pearce, midfielder Danny Williams, winger Hal Robson-Kanu and striker Pavel Pogrebnyak all dropped out of the squad for Wednesday night’s defeat by Birmingham after picking up knocks against Arsenal in the FA Cup semi-final.
Boss Steve Clarke will also be without utility man Nathan Ake, who started against City but has now gone back to Chelsea after his loan spell came to an end.
Defensive duo Jure Travner (groin) and Anton Ferdinand (calf) are still missing.
Brentford make the short trip along the M4 without on-loan Everton youngster Chris Long.
The striker, who recently extended his stay with the Bees, has been ruled out after suffering a knee injury.
Midfielder Lewis Macleod is still not match fit after a hamstring problem and forward Scott Hogan continues his recovery from cruciate ligament damage.
But the Bees are otherwise in good shape as they attempt to make up ground on the play-off places.