Relegation-threatened Livorno have sacked Domenico Di Carlo after just 88 days in charge and re-appointed Davide Nicola.
Virgil van Dijk claims he knows nothing of interest from English clubs and is keen to prove himself in the Champions League with Celtic.
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.