Abu Ahmad al-Hakim: Not strong according to them
Abu Ahmad ibn Adi al-Jurjani: In his narrations there are some unknown things
Abu Hatim ibn Hibban al-Busti: He narrates fabricated reports from the trustworthy narrators
Abu Dawud al-Sijistani: He is nothing
Abu Isa al-Tirmidhi: He narrated from al-Bukhari that he said: He has munkar narrations
Abu Nuaym al-Fadl ibn Dukin: Trustworthy
Ahmad ibn Hanbal: His hadiths are munkar
Ahmad ibn Shuayb al-Nasa'i: Weak
Ibn Hajar al-'Asqalani: Weak
al-Daraqutni: Weak, abandoned, he mentioned him among the weak and abandoned narrators
al-Dhahabi: One of the worshippers, his hadith was abandoned
Yahya ibn Sa'id al-Qattan: Perished
Yahya ibn Ma'in: His hadith is nothing, and once: He is nothing, and once: Sayf is more beloved to me than Sinan, and once: He is not like that, and once: Sayf ibn Harun and Sinan ibn Harun are weak