diff --git a/tensorflow/python/keras/engine/network.py b/tensorflow/python/keras/engine/network.py
index 9815d17080e..26196209226 100644
--- a/tensorflow/python/keras/engine/network.py
+++ b/tensorflow/python/keras/engine/network.py
@@ -1796,12 +1796,15 @@ def _map_graph_network(inputs, outputs):
       nodes_depths[inbound_node] = max(depth + 1, previous_depth)
 
   # Handle inputs that are not connected to outputs.
+  # We do not error out here because the inputs may be used to compute losses
+  # and metrics.
   for input_t in inputs:
     input_layer = input_t._keras_history[0]
     if input_layer not in layers_depths:
       layers_depths[input_layer] = 0
       layer_indices[input_layer] = -1
       nodes_depths[input_layer._inbound_nodes[0]] = 0
+      network_nodes.add(_make_node_key(input_layer.name, 0))
 
   # Build a dict {depth: list of nodes with this depth}
   nodes_by_depth = collections.defaultdict(list)
diff --git a/tensorflow/python/keras/engine/network_test.py b/tensorflow/python/keras/engine/network_test.py
index 6748ecfe126..3aa5024d8a6 100644
--- a/tensorflow/python/keras/engine/network_test.py
+++ b/tensorflow/python/keras/engine/network_test.py
@@ -968,6 +968,18 @@ class NetworkConstructionTest(keras_parameterized.TestCase):
     w = model.add_weight('w', [], initializer=keras.initializers.Constant(1))
     self.assertEqual(dtypes.int64, w.dtype)
 
+  def test_disconnected_inputs(self):
+    input_tensor1 = input_layer_lib.Input(shape=[200], name='a')
+    input_tensor2 = input_layer_lib.Input(shape=[10], name='b')
+    output_tensor1 = keras.layers.Dense(units=10)(input_tensor1)
+
+    net = keras.engine.network.Network(
+        inputs=[input_tensor1, input_tensor2], outputs=[output_tensor1])
+    net2 = keras.engine.network.Network.from_config(net.get_config())
+    self.assertLen(net2.inputs, 2)
+    self.assertEqual('a', net2.layers[0].name)
+    self.assertEqual('b', net2.layers[1].name)
+
 
 class DeferredModeTest(test.TestCase):