Musannaf Ibn Abi Shayba 35:322

Abu Khalid al-Ahmar narrated to us, from Ibn Abi Dhi'b, from Salih, the freed slave of al-Taw'ama, who said: Marwan appointed Abu Hurayrah as a deputy over Medina. He used to lead us in prayer on Friday, and he would deliver two sermons and sit for two sittings. And he mentioned that Abu Hanifah said: He does not sit except for one sitting.