Parashas Vayeishev · Passuk 37:2
These are the generations of Yaakov: Yosef, being seventeen years old, was feeding the flock with his brothers; and he was a lad with the sons of Bilhah, and with the sons of Zilpah, his father’s wives; and Yosef brought their evil report unto their father.
Torah Temimah points to Sotah 36b.
English: It was taught: Yosef was fit to have twelve tribes issue from him just as they issued from his father Yaakov, as it is stated “These are the generations of Yaakov — Yosef.” But his seed issued from between his fingernails. Nevertheless, they issued from his brother Binyamin, and all of them were called by his name.
Derash on the verse (Bavli sugya) — not a formal named middah of the 13. The juxtaposition “generations of Yaakov — Yosef” is read as indicating that Yosef was destined for the full complement of tribes.
Yosef was worthy to father twelve tribes, as indicated by the verse’s wording. That potential was lost, yet the tribes later associated with Binyamin were named after him.