Dortmund are believed to have been offered the defender by Rayo Vallecano earlier in the year for around £3m.
However, the former German champions turned down a move, with Galvez later signing for Werder.
"We met in a hotel and talked about a change," Galves told Bild.
"I had an exit clause of €4m (£3.2m) but Dortmund did not want to pay for it. Then they decided to [go for Greece international] Sokratis Papastathopoulos.
"It would have been a good option but I knew that a new one would come along. Werder is a new option."
Galvez spent two years with Rayo.