diff --git a/vllm/v1/executor/uniproc_executor.py b/vllm/v1/executor/uniproc_executor.py
index be058318de58..9b7b25196ff5 100644
--- a/vllm/v1/executor/uniproc_executor.py
+++ b/vllm/v1/executor/uniproc_executor.py
@@ -70,6 +70,7 @@ def execute_model(
         scheduler_output,
     ) -> ModelRunnerOutput:
         output = self.worker.execute_model(scheduler_output)
+        assert output is not None
         return output
 
     def profile(self, is_start: bool = True):
diff --git a/vllm/v1/worker/gpu_worker.py b/vllm/v1/worker/gpu_worker.py
index e83bce428355..eb2f39e00a99 100644
--- a/vllm/v1/worker/gpu_worker.py
+++ b/vllm/v1/worker/gpu_worker.py
@@ -199,7 +199,7 @@ def compile_or_warm_up_model(self) -> None:
     def execute_model(
         self,
         scheduler_output: "SchedulerOutput",
-    ) -> ModelRunnerOutput:
+    ) -> Optional[ModelRunnerOutput]:
         output = self.model_runner.execute_model(scheduler_output)
         return output if self.rank == 0 else None