Musannaf Ibn Abi Shayba 3:4912

Ghundar narrated to us, from Shu'bah, who said: I asked Hammad about a man who prays and sees blood on his garment. He said: "He should cast the garment away from himself." I said: "What if he has no other than two garments?" He said: "He should cast one of them away and wrap himself in the other." And I asked al-Hakam, and he said the like of that.