Because his mother's sister was the wife of MINAMOTO no Sanetomo, he was temporarily slated for appointment as a prospective seii taishogun (literally, "great general who subdues the barbarians") after Sanetomo died a sudden death in 1219.
母の姉妹が源実朝の室だった関係もあり、建保7年（1219年）の実朝横死後は一時後継の征夷大将軍候補に擬せられていた。