The Mexico international has struggled to establish himself in the first team at Craven Cottage since moving from PSV Eindhoven last summer.
Salcido appears to have dropped down the pecking order with the Cottagers following the arrival of former Liverpool defender John Arne Riise this week.
And with the emergence of youngster Matthew Briggs, the 31-year-old full-back's days in west London appear to be numbered.
Jol said: "It depends on the conditions. We've only got 17 or 18 senior pros left and a lot of youngsters.
"Our second XI is not good enough yet. If we don't get the right deal for Salcido he will stay."