I recently read a hadith purportedly from al-Irshad by Shaykh Tusi which stated that Abu Dujanah al-Ansari- which I take to mean the sahabi of the Prophet famous for his skill in combat- will arise with the Mahdi to support him, along with many other people (such as Malik Ashtar and the Seven Sleepers).  Could anyone shed light on this hadith, and our view on Abu Dujanah?