The 31-year-old will now miss up to three months of action following an injury sustained in training, leaving Djibril Cisse and Jamie Mackie as the only recognised strikers
The striker suffered the damage in a recent training session, and the club have revealed on their website that the 31-year-old will require an "exploratory operation" to determine the extent of the injury.
The striker has scored six goals in 22 appearances for the R’s following his move from city rivals Fulham in January 2012, and leaves just Djibril Cisse and Jamie Mackie as the only recognised strikers following Andy Johnson’s long-term spell on the sidelines.
The west London club are still without a win after 12 games this season, with four draws and eight defeats leaving them five points clear of safety.
QPR's latest 3-1 defeat at home to fellow strugglers Southampton leaves them adrift at the bottom of the league, with mounting pressure on chairman Tony Fernandes to replace the beleaguered coach Mark Hughes.