Musnad Ahmad 1153:431

Husayn narrated to us, he said: Ibn Abi al-Zinad narrated to us, from al-A’raj, from Abu Hurayrah, from the Prophet, peace and blessings of Allah be upon him, the like of it. Abu Abd al-Rahman said: "And this, I see that in it is 'from his father, from al-A’raj,' but it was thus in the book. So I do not know if my father neglected it, or if it is thus Mursal (disconnected)."