diff --git a/var/spack/repos/builtin/packages/root/package.py b/var/spack/repos/builtin/packages/root/package.py
index dff3e048db362f..0f7a82c9d64984 100644
--- a/var/spack/repos/builtin/packages/root/package.py
+++ b/var/spack/repos/builtin/packages/root/package.py
@@ -713,7 +713,7 @@ def cmake_args(self):
             options.append(define_from_variant("tmva-sofie"))
 
         if self.spec.satisfies("@:6.30"):
-            define_from_variant("minuit2", "minuit"),
+            options.append(define_from_variant("minuit2", "minuit"))
 
         # #################### Compiler options ####################