The Cottagers steered well clear of the relegation battle this season, although they failed to kick on once they had passed the 40-point mark with four defeats from the past five Premier League matches.
Dutchman Jol saw his best laid plans for the campaign ripped apart ahead of the August transfer deadline when he lost Mousa Dembele and Clint Dempsey to big-money moves to rivals Tottenham.
Striker Dimitar Berbatov has been strongly linked with a switch to Russian side Zenit St Petersburg, while Greek midfielder Giorgos Karagounis and veteran goalkeeper Mark Schwarzer are both out of contract.
Riether was one of several players brought in by Jol on loan deals, and hopes to make his transfer from Cologne permanent. The 30-year-old is in no doubt the west London club can kick on again next season, no matter what changes in personnel may occur.
"At Fulham it is always possible that you might lose great players, big players, to other clubs so it is not easy," Riether said in the London Evening Standard.
"It is normal that if you play well other clubs want to buy you.
"If some players do leave, other good players will come and I think Fulham will have a great team next year."