Movies and Lore - Why didn't Sauron recruit the Balrog from Moria?

Movies & Lore - Why didn't Sauron recruit the Balrog from Moria? Music by: "Keys Of Moon - Silhouette of War" is under a Creative Commons (CC-BY 3.0) license Music promoted by BreakingCopyright: https://bit.ly/bkc-silhouette