Ata' (may Allah have mercy on him) narrates from Ibn Abbas (may Allah be pleased with them both) that, about a man who vowed to slaughter himself, he said: "There is for you in the Messenger of Allah (peace and blessings be upon him) an excellent example" [Surah al-Ahzab: 21], and he gave him the ruling to slaughter a ram.
This indicates that the narration of Uthman bin Umar is an error; and others besides Sufyan narrated it likewise from Ibn Jurayj.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 20082