De Bruyne is spending the campaign on loan at Bremen to build up his experience after joining Chelsea from Genk on a contract until 2017 last year.
The Belgium international has impressed during his time at Bremen and it has prompted speculation the Bundesliga club will try to sign the 21-year-old permanently.
His agent has played down such a scenario, but Schaaf is hoping that De Bruyne could still be part of his plans next season.
"I would be kind of stupid not to want to keep such an exceptionally talented player at our club longer," Schaaf told Deutsche Pressagentur.
"Of course, we will have to wait and see what Chelsea FC intends to decide on Kevin de Bruyne's future.
"Generally, he has been a big boost for our squad. We profit because he is giving his best in the games for our club and we offer him every chance to impress while he is on loan.
"He's a great player. And Kevin told me recently how much he enjoys being at Werder Bremen.
"It's obvious that he has not yet reached his own maximum. I would be delighted to keep on working with him beyond the end of the season that's for sure."