פירוש על קידושין 37:2

R. Nahman b. Yitzchak says that R. Yose b. R. Yehudah holds that the original sale money counts as kiddushin money. Should the master designate her, he need not give more kiddushin money. But then we have a problem—the father essentially betrothed her when he sold her? How can he sell her again?
The answer is that this baraita agrees with R. Eliezer who had said that a father may sell his daughter for servitude after marriage.