With the Loftus Road side still yet to win a league match this season, the 31-year-old's absence heaps more pressure on manager Mark Hughes.
The west London side's next game after hosting Nigel Adkins' team is a trip to face Manchester United, and while Hughes is hopeful that the South Korean will be back for the game against his former club, he also revealed that Kieron Dyer could make a return.
Hughes told West London Sport: "Ji's been struggling with his knee but we're hopeful he'll start training and then figure, possibly not this weekend, but the one after.
|14/1||Southampton are 14/1 with bet365 to beat QPR 1-0 next weekend|
The 33-year-old Dyer is currently back in training after recovering from a calf injury.