The Brazilian youngster is on a two-season loan in Dortmund, though it had been suggested he would seek to terminate the deal this month after a tough first six months.
But Goal says Reinier remains committed to the loan.
The midfielder has just turned 19 and has not played a game as a starter this season in Germany. He has participated in eight matches, for a total of 136 minutes.
Real Valladolid have expressed interest in taking over Reinier's loan this month.