diff --git a/kharma/reductions/reductions_variables.hpp b/kharma/reductions/reductions_variables.hpp
index 0ebe3681..46071eb2 100644
--- a/kharma/reductions/reductions_variables.hpp
+++ b/kharma/reductions/reductions_variables.hpp
@@ -58,7 +58,7 @@ enum class Var{phi, bsq, gas_pressure, mag_pressure, beta,
 
 // Function template for all reductions.
 template<Var T>
-Real reduction_var(REDUCE_FUNCTION_ARGS);
+KOKKOS_INLINE_FUNCTION Real reduction_var(REDUCE_FUNCTION_ARGS);
 
 // Can also sum the hemispheres independently to be fancy (TODO?)
 template <>
@@ -249,4 +249,4 @@ KOKKOS_INLINE_FUNCTION Real reduction_var<Var::neg_rho>(REDUCE_FUNCTION_ARGS)
 
 }
 
-#undef REDUCE_FUNCTION_ARGS
\ No newline at end of file
+#undef REDUCE_FUNCTION_ARGS