The Germany international has struggled to force his way into the Tottenham starting line-up after scoring one goal in six Premier League starts this season.
Lewis is desperate to play
Holtby moved to the north London side in a £1.5m deal from Schalke in the January transfer window last year after impressing for the Bundesliga side.
However the 23-year-old’s chances of being included in Joachim Low’s Germany squad for this summer’s World Cup are being damaged due to a lack of football.
And Holtby’s agent Noack confirmed he is looking to find a solution for the playmaker, which could potentially include a return to his former club.
“Lewis is desperate to play, which is why we are looking intensively for solutions,” Noack told Bild.
“Schalke is an interesting option.”
Holby has scored three goals in 36 appearances in all competitions since moving to White Hart Lane in 2012.
MORE: Man United latest news
MORE: Arsenal latest news
MORE: Chelsea latest news
MORE: Liverpool latest news