A rabbi in Yemen said to me, "If your companion is indeed a prophet, then he has died today."Jareer said, He died on Monday. ﷺ
حدثنا أبو سعيد مولى بني هاشم حدثنا زائدة حدثنا زياد بن علاقة
قال لي حبر باليمن إن كان صاحبكم نبيا فقد مات اليوم قال جرير فمات يوم الاثنين ﷺ
No references are available.
Its isnad is sahih, and Ahmad narrated it alone, but it is not a hadith.