Riether joined Fulham on a season-long loan from Cologne last summer and he has made 30 appearances in all competitions, missing just one game in the Premier League.
Fulham have first option to retain the 29-year-old and Jol reiterated his intention to ensure Riether is part of his squad next season.
"Sascha is a fans' favourite," Jol told Deutsche Pressagentur. "He is the right-back in my starting XI.
"He runs, he works and he has a good view of situations. I am glad to have him at this club.
"We possess an option [to buy him]. If we are to exercise it, he will have to remain at our club. But if he is not happy, we would have to talk then.
"But I really don't think that this is the case with him. I think he feels fine being a first-team regular with us."
Illness forced Riether to miss the 0-0 draw at Norwich City earlier this month when he was replaced by January signing Stanislav Manolev, but he returned to the team for last Saturday's 1-0 win over Stoke City.