diff --git a/lib/spack/spack/solver/asp.py b/lib/spack/spack/solver/asp.py
index 94cc35d8dee..55573518de3 100644
--- a/lib/spack/spack/solver/asp.py
+++ b/lib/spack/spack/solver/asp.py
@@ -764,7 +764,8 @@ def virtual_preferences(self, pkg_name, func):
                 continue
 
             for i, provider in enumerate(providers):
-                func(vspec, provider, i + 10)
+                provider_name = spack.spec.Spec(provider).name
+                func(vspec, provider_name, i + 10)
 
     def provider_defaults(self):
         self.gen.h2("Default virtual providers")