The 31-year-old midfielder made over 60 appearances for the West London club before a 1998 move to Nottingham Forest.
At the City Ground, the Scotland international started 37 league games before making Portsmouth the next step in a nomadic career.
Now back at Loftus Road, Quashie could make his second R's debut in Tuesday night's Championship clash against the Reds, where Forest's potential downfall will be plotted by former caretaker boss Mick Harford, currently performing a similar role with the R's.