diff --git a/fastapi/dependencies/utils.py b/fastapi/dependencies/utils.py
index 1a493a9fd..91348c8ea 100644
--- a/fastapi/dependencies/utils.py
+++ b/fastapi/dependencies/utils.py
@@ -548,10 +548,10 @@ async def _solve_generator(
     *, dependant: Dependant, stack: AsyncExitStack, sub_values: Dict[str, Any]
 ) -> Any:
     assert dependant.call
-    if dependant.is_gen_callable:
-        cm = contextmanager_in_threadpool(contextmanager(dependant.call)(**sub_values))
-    elif dependant.is_async_gen_callable:
+    if dependant.is_async_gen_callable:
         cm = asynccontextmanager(dependant.call)(**sub_values)
+    elif dependant.is_gen_callable:
+        cm = contextmanager_in_threadpool(contextmanager(dependant.call)(**sub_values))
     return await stack.enter_async_context(cm)