Aston Villa manager Tim Sherwood has revealed in-demand defender Ron Vlaar has told him he wants to stay at the club.
Arsenal manager Arsene Wenger believes squad size is crucial ahead of a potentially busy summer of transfer activity.
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.