diff --git a/python_modules/dagster/dagster/_core/execution/plan/execute_step.py b/python_modules/dagster/dagster/_core/execution/plan/execute_step.py
index caaeb6e6a0a6f..74d4ae030c2b1 100644
--- a/python_modules/dagster/dagster/_core/execution/plan/execute_step.py
+++ b/python_modules/dagster/dagster/_core/execution/plan/execute_step.py
@@ -779,10 +779,14 @@ def _gen_fn():
         yield DagsterEvent.asset_materialization(step_context, materialization)
 
     asset_key, partitions = _asset_key_and_partitions_for_output(output_context)
-    asset_layer = step_context.job_def.asset_layer
-    if asset_key and asset_layer.has_assets_def_for_asset(asset_key):
-        assets_def = asset_layer.assets_def_for_asset(asset_key)
-        execution_type = assets_def.asset_execution_type_for_asset(asset_key)
+    if asset_key:
+        asset_layer = step_context.job_def.asset_layer
+        execution_type = (
+            asset_layer.assets_def_for_asset(asset_key).asset_execution_type_for_asset(asset_key)
+            if asset_layer.has_assets_def_for_asset(asset_key)
+            else AssetExecutionType.MATERIALIZATION
+        )
+
         check.invariant(
             execution_type != AssetExecutionType.UNEXECUTABLE,
             "There should never be unexecutable assets here",