Abu Hurairah came and stayed in Damascus, lodging with Abu Kulthum al-Dawsi. They discussed the middle prayer, and he said, "We disagreed about it just as you have disagreed, while we were in the courtyard of the Messenger of Allah's ﷺ house. Among us was the righteous man Abu Hashim bin Utbah. He got up and went in to the Messenger of Allah ﷺ, for he was bold with him, then he came out and informed us that it is the afternoon prayer."
عن أبي هريرة أنه أقبل حتى نزل دمشق، فنزل على أبي كلثوم الدوسي، فتذاكروا الصلاة الوسطى فقال: اختلفنا كما اختلفتم، ونحن بفناء بيت رسول الله ﷺ، وفينا الرجل الصالح: أبو هاشم بن عتبة، فقام فدخل على رسول الله ﷺ، وكان جريئا عليه، ثم خرج إلينا فأعلمنا أنها صلاة العصر.
Bazzar narrated it in Kashf Astar (391) from Ahmad bin Mansur, who said that Hisham bin Ammar narrated to them, who said that Sadaqah, namely Ibn Khalid, narrated to them, who said that Khalid bin Dahqan narrated to them, who said that Khalid Sablan told him, from Kuhayl bin Harmalah, and he mentioned something similar.Bazzar said, "We do not know of Abu Hashim bin Utbah narrating from the Prophetﷺ except this hadith and one other." End of quote.Haythami attributed it in Majma (1/309) to Tabarani in Kabir as well, and said, "Its narrators are deemed trustworthy."Hakim also recorded it (3/638) via Khalid bin Dahqan, with the same wording, and said nothing about it. Its chain of transmission is hasan because of Khalid bin Dahqan, for Ibn Main and Darimi both deemed him trustworthy.As for Khalid Sablan, he is Khalid bin Abdullah bin Faraj, Abu Hashim, the freedman of Banu Abs, known as Khalid Sablan. He was given this nickname because of how long his beard was, as the editor of Thiqat by Ibn Hibban mentioned in a footnote, quoting from the Tarikh of Ibn Asakir.See Tahdhib Tarikh Ibn Asakir (5/67). Ibn Hibban also mentioned him in Thiqat (6/255).