On-loan defender Martin Cranie suffered a fractured fibula in the 2-1 defeat to Coventry City on Tuesday night.
The Portsmouth loanee was forced from the fray in the 20th minute against the Sky Blues.
The England Under-21 international went straight to hospital for an X-ray, which confirmed the fracture.
Cranie will return to Portsmouth for his rehabilitation.
"It's a great shame," R's physio Paul Hunter told www.qpr.co.uk.
"It's a similar injury to the one Simon Walton sustained in pre-season.
"Martin has been fantastic since he joined us and it's a real blow. We wish him all the best with his recovery."
Meanwhile, Mikele Leigertwood is inked in to see a specialist later today after he suffered a broken nose on Tuesday evening.
Marc Nygaard was also ruled out in the first half and the Great Dane will have a scan on his hamstring this afternoon.