diff --git a/go/vt/vtgate/planbuilder/operators/route.go b/go/vt/vtgate/planbuilder/operators/route.go
index 551d7b6d95e..8588333eba9 100644
--- a/go/vt/vtgate/planbuilder/operators/route.go
+++ b/go/vt/vtgate/planbuilder/operators/route.go
@@ -719,7 +719,8 @@ func (r *Route) GetOrdering(ctx *plancontext.PlanningContext) []OrderBy {
 // in Inputs() and thus not a part of the operator tree
 func (r *Route) TablesUsed(in []string) []string {
 	for _, mw := range r.MergedWith {
-		in = append(in, mw.TablesUsed(in)...)
+		used := TablesUsed(mw)
+		in = append(in, used...)
 	}
 	return in
 }