The Cottagers steered well clear of the relegation battle this season, if failing to kick on once they had passed the 40-points mark with four defeats from the past five Barclays 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 arrive.
"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.
Riether added: "It was not easy for us after losing very good players like Dembele and Dempsey, who scored a lot of goals last season.
"Our goal was to be in the top 10, hopefully we can reach that and then it is important to build on that for next season.
"There will be a lot of changes in the team this summer. Some new players will join, some players will leave, but we will be prepared for next season.
"The Premier League is not easy, but we can build step by step.
"Our recent form is not very good but we have played teams like Chelsea, Arsenal and Everton. Two of our three remaining games are at home, so I think we can finish strongly."
Full-back Riether is hopeful of returning from an ankle injury for Saturday's home game against relegated Reading.
The German, who is in talks with Fulham over pushing through a £1.3million deal, feels his transition to the hectic pace of English top-flight football has gone well.
"You never know what will happen in a new league, it was not easy coming to another country with a different style of football, but it has gone well for me," he said.
"German football and English football are different, so I had to adapt to a new style of play and new team-mates. Little by little it has got better and I hope that continues.
"Football in Germany is always physical and people like to see that in England - the fans like me and my style because I always give 100%."