diff --git a/orttraining/orttraining/eager/opgen/opgen/atenops.py b/orttraining/orttraining/eager/opgen/opgen/atenops.py
index 75efd71f7f..58bb63fb97 100644
--- a/orttraining/orttraining/eager/opgen/opgen/atenops.py
+++ b/orttraining/orttraining/eager/opgen/opgen/atenops.py
@@ -159,7 +159,9 @@ hand_implemented = {
     "aten::eq.Scalar_out": Cast(Equal("self", "other"), to="GetONNXTensorProtoDataType(out.scalar_type())"),
     "aten::bitwise_and.Tensor_out": MakeTorchFallback(),
     "aten::masked_select": GatherND("self", Transpose(NonZero(Expand("mask", Shape("self"))))),
-    "aten::_local_scalar_dense": MakeTorchFallback(),
+    "aten::_local_scalar_dense": MakeTorchFallback(),  # This function extracts a scalar value from
+    #   a tensor with exactly one value; there's no need to try to do this on an ORT device.
+    #   See CPU impl at pytorch/blob/master/aten/src/ATen/native/Scalar.cpp
     "aten::gt.Scalar_out": MakeTorchFallback(),
     "aten::lt.Scalar_out": MakeTorchFallback(),
     "aten::equal": SignatureOnly(),