Royals midfielder Danny Guthrie has a thigh injury and is not available for Sunday's trip to QPR.
The former Newcastle man, who has played six times for the Royals this summer and scored once, picked up the injury in training on Monday and the problem requires a scan.
Danny was working in the gym with Jem Karacan at Hogwood Park this morning and Brian McDermott said, "Danny pulled his thigh in training on Monday so he won't be available, I don't know at the moment how long it'll be, we'll have to wait and see.
"Obviously Jem is out as well at the moment but other than that I think everybody is OK."
Rangers are without the suspended Stephane Mbia, while Fabio and Andy Johnson are also ruled out.
QPR boss Mark Hughes said in his pre-match press, "Bobby [Zamora] has had a couple of injections in his hip. He trained today and we’ve got to make sure there’s no reaction from that. Hopefully he’ll be available. He’s a little bit stiff, we’ll have to wait and see.
"Ji[-Sung Park] hasn't trained this week, he’s an obvious doubt for the weekend. We’ll see how he is tomorrow but at this moment in time he’s very unlikely to take part. There’s a bit of a doubt over Armand Traore as well. Apart from that and the long-term injuries that’s where we’re at."