The 21-year-old has been a long term target for Scottish giants Celtic.
After initially struggling to hold down a place in Ian Holloway's side, Manning has shone on the right side of midfield in recent weeks.
It is understood Holloway wants to keep ahold of Manning as he sees him as a future regular at Loftus Road.
But Financial Fair Play regulations may force the west London club to sell one of their prized young assets.
And Football Insider believe Palace are interested in taking Manning off Rangers' hands and could launch a bid this summer.