Abu Hatim al-Razi: Saduq (truthful)
Abu Hatim ibn Hibban al-Busti: He mentioned him among the Thiqat
Abu Dawud al-Sijistani: I do not narrate from Fadl ibn Sahl al-A'raj. He was asked: Why? He said: Because he would not miss a good hadith.
Ahmad ibn al-Husayn al-Sufi al-Saghir: He was one of the calamities. Al-Khatib said: Meaning in intelligence, knowledge, and the goodness of his hadiths.
Ahmad ibn Shu'ayb al-Nasa'i: Thiqah
Ibn Hajar al-'Asqalani: Saduq (truthful)
Al-Dhahabi: He was intelligent and had a good memory.
Authors of Tahrir Taqrib al-Tahdhib: Thiqah, and al-Jumm al-Ghafir narrated from him from among the Thiqat, and the two Sheikhs narrated from him in their Sahihs.