Sforno on Genesis 38:1/ספורנו על בראשית ל״ח:א׳

1ויהי בעת ההיא, והמדנים מכרו אותו, [the Torah contrasts the facts with the perception of the facts, i.e. Joseph was alive but the Midianites had sold him. I believe that this is why the author quotes the beginning of this verse without elaborating on it at all. He leaves it to our imagination to fill in this next item in the tragic chain of errors beginning with the fact that Yitzchok had shown more love for Esau. Ed.] at about the same time when Joseph was sold to Egypt at the suggestion of Yehudah who had proposed this instead of bringing him back to his father and had thereby bereaved his father, Yehudah reaped some of the fruit of his ill advised plans, in that the way was paved for him to be bereaved of two of his own sons in due course.