The versatile 29-year-old, who joined Rushden after leaving Loftus Road in 2002, is discussing a return to west London ahead of the transfer deadline.
Bignot had spells with Kidderminster and Crewe before playing under Ian Holloway at Bristol Rovers and QPR.
Now the R's boss is looking to re-sign him amid concern over the fitness of Gino Padula, Terrell Forbes and Matthew Rose.
Bignot made 57 appearances for Rangers during his previous spell with the club.