Sunderland are yet to make a formal offer for Fer but are understood to have enquired about the Netherlands international’s services, although they could face competition for his signature from West Ham.
A loan deal has been mooted for the former Feyenoord midfielder, who made 32 appearances for QPR last term after joining the club in an £8m deal from Norwich a year ago.
Sunderland boss Dick Advocaat is also understood to be interested in signing Rubin Kazan midfielder M’Vila.
The France international made a surprise £10m move to Rubin from Ligue 1 side Rennes two-and-a-half years ago after being linked with a host of top European clubs.
M’Vila spent last season on loan at Inter Milan and looked set for another temporary move to Dinamo Moscow after a dispute with his parent club.
But Sunderland are hoping to lure the midfielder to Wearside after already completing summer deals for Jeremain Lens, Younes Kaboul, Ricky Alvarez, Adam Matthews and Sebastian Coates.
Follow 92Live throughout Tuesday on Sky Sports News HQ, with our live blog on Sky Sports digital platforms and on Twitter by following @SkySportsNewsHQ, using #92Live.