Dimitar Berbatov has been linked with a move away from the club, while the Cottagers have also got over 10 players whose deals run out at the end of the season.
"You can use that cliche the grass is always greener here, probably, and not at another place," Jol told reporters.
"There is a lot of evidence of players leaving this club and they had a better time here, maybe 80 or 90% of the players. But that is quite arrogant to say, because other players go on to bigger clubs.
"Was there one player going to a top club or another club and did better than here? I don't think so."
Fulham are currently 11th in the Premier League, eight points clear of the relegation zone.