Shaun Wright-Phillips insists he is happy again at QPR after turning down "offers and opportunities" to move in January.
Blackburn goalkeeper Paul Robinson has told Sky Sports he will leave the club this summer and could move abroad.
Fox has sunk down the pecking order at St Mary's following the emergence of England Under-21 left-back Luke Shaw.
Now Bolton have made a move to land Fox, who has featured just once for the Saints this term.
Fox will join Bolton until January, when they could opt to make the move permanent.
Fox is set to be the latest loan recruit for Bolton, who snapped up Liam Feeney from Millwall, Neil Dann from Leicester and Cardiff's Kevin McNaughton last week.