The 34-year-old has performed with aplomb recently, netting five goals in as many games, including a brace in the 3-2 defeat of Stoke on Saturday.
QPR could only name five substitutes for the Britannia Stadium clash for various reasons and manager Neil Warnock on Wednesday spoke on Helguson to the club's official website, www.qpr.co.uk: "Unfortunately, Heidar has not joined in yet this week and there's a doubt over him for Saturday's game at Norwich."
He also revealed the extent of the club's other injury problems, saying: "Sadly Brian Murphy is going to be out for a few weeks with the calf injury he picked up [in the warm-up], but Jason Puncheon is back in training [after tonsillitis].
"Luke [Young] came off with a knee injury as a precaution, but we are optimistic he is going to join in training on Thursday."
Armand Traore also struggled against Stoke but managed to play the full 90 minutes, with Warnock adding: "He has got a persistent thigh problem that we're managing."
Jay Bothroyd and Danny Gabbidon are both expected to resume light training on Thursday after their own fitness concerns, while DJ Campbell (foot) is continuing to do strengthening work on his calf and thigh.
In addition, long-term absentees Matt Connolly (ankle) and Kieron Dyer (foot) have stepped up their running this week.
Source: PA
Source: PA