Gines Carvajal did not name the interested team but said a decision on the Spaniard's future will be made in the coming days.
The 34-year-old, whose contract runs out in the summer, has been holding out for a two-year extension at the Veltins Arena, while the club are only willing to offer a one-year deal.
"Raul will make his decision in a few days," Carvajal told Cadena COPE. "He has an offer from another Bundesliga club.
"But Raul wants to play only for Schalke in the Bundesliga."
The ex-Real Madrid striker has also been linked with a lucrative move to the Middle East to play for Qatari club Al Rayyan, following in the footsteps of former team-mate Fernando Hierro.
Schalke are currently third in the Bundesliga standings, nine points behind leaders Borussia Dortmund.
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