Schalke will be sending Jean-Clair Todibo back to Barcelona at the end of this season.
The 20-year-old has played 10 games for Schalke in all competitions since joining the club on loan in January.
"We no longer have an option to buy Todibo," explained Jochen Schneider, Schalke's sporting director.
"The deadline expired yesterday [May 31]."
In principle, Todibo is not in Barcelona's plans and they will look to move him on this summer.