Musnad Abu Ya'la al-Mawsili 110:92

And from Haql, who said: I heard al-Awza'i, who said: al-Zuhri narrated to us, from 'Ubayd Allah ibn 'Abd Allah ibn 'Utbah, from Ibn 'Abbas, that the Messenger of Allah (peace be upon him) passed by a dead sheep and said: "Why did you not make use of its skin?" They said: "O Messenger of Allah, it is dead (carrion)." He said: "Only its eating has been forbidden."