diff --git a/lib/qcd/action/fermion/WilsonFermion.h b/lib/qcd/action/fermion/WilsonFermion.h
index c050c0eb..3a1ba432 100644
--- a/lib/qcd/action/fermion/WilsonFermion.h
+++ b/lib/qcd/action/fermion/WilsonFermion.h
@@ -78,7 +78,7 @@ namespace Grid {
       virtual void MooeeInv(const FermionField &in, FermionField &out) ;
       virtual void MooeeInvDag(const FermionField &in, FermionField &out) ;
 
-      virtual void  MomentumSpacePropagator(FermionField &out,const FermionField &in) ;
+      virtual void  MomentumSpacePropagator(FermionField &out,const FermionField &in,RealD _mass) ;
 
       ////////////////////////
       // Derivative interface