Rob Dickie is the latest key QPR player to be ruled out for the rest of the season.
Dickie has suffered a hamstring injury and will not be available for the remaining games of what is turning into a hugely disappointing campaign.
Rangers, part of the promotion race for most of the season, saw their play-off hopes dwindle further as they were beaten 2-1 at Preston – their fifth consecutive defeat and seventh in eight matches.
They have struggled badly without Chris Willock, whose season was recently ended by a hamstring injury.
Hopes are also fading that Seny Dieng – one of four QPR goalkeepers out injured – will return before the end of the season.
On-loan midfielder Jeff Hendrick also has a hamstring problem, although it appears to be less serious.
Rangers were without Dickie, Hendrick, Yoann Barbet and Lee Wallace for the loss at Deepdale.
The result cast further doubt over the future of manager Mark Warburton, who believes Barbet and Wallace might be available for Friday’s game at Huddersfield.
Warburton said: “I hope Yoann will be maybe a week. He’s had a swollen knee but that will hopefully go down. Lee Wallace, the same, hopefully will be available.”