Middlesbrough striker Scott McDonald has consulted a specialist over his fight for fitness after hernia surgery.
The former Celtic frontman arrived at the Riverside Stadium last month having already had his operation but has struggled to shake off the after-effects and is a major doubt for the Coca-Cola Championship clash with QPR.
However, New Zealand international Chris Killen is expected to return to the squad after recovering from the hamstring problem and virus which have kept him out of the last three games.
Rhys Williams (pelvic injury) and Chris Riggott (hamstring) are back in training but defender Tony McMahon is out with a stress fracture of the foot.
Long-term absentees Seb Hines (ankle and medial ligament) and Matthew Bates (cruciate ligament) remain on the sidelines.
QPR caretaker boss Mick Harford is boosted by the return of midfielder Mikele Leigertwood.
Leigertwood has served a three-match ban for his dismissal in the 1-0 defeat to Peterborough, but defender Matthew Connolly could well miss out.
The 22-year-old picked up an ankle injury during last weekend's clash with Doncaster and is facing a race against time to be fit.
On-loan striker Tamas Priskin has returned to training following a groin problem and is pushing for a place in the starting line-up.
Fellow loanee Marcus Bent missed last weekend's win over Doncaster with a hamstring injury and will be absent once again.
Rangers are still without long-term knee-injury victims Martin Rowlands and Gavin Mahon. Rowlands' injury will keep him out for the rest of the season but the club hope fellow midfielder Mahon will be pushing for a return by April.
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