The USA inernational's progress with VCF since his arrival from Arsenal has impressed BVB scouts.
In the friendly between the two clubs on Monday, the 19-year-old shone in midfield against the Black and Yellows.
And BVB officials asked Valencia about a price for Musah.
The flexible midfielder is tied to the Spaniards until 2026. Although his release clause is €100m, Valencia are said to be ready to talk from €20m.