diff --git a/.coveragerc b/.coveragerc
index 8ba0356fa9c..3c7f7640623 100644
--- a/.coveragerc
+++ b/.coveragerc
@@ -633,6 +633,7 @@ omit =
     homeassistant/components/mjpeg/camera.py
     homeassistant/components/mochad/*
     homeassistant/components/modbus/climate.py
+    homeassistant/components/modbus/modbus.py
     homeassistant/components/modem_callerid/sensor.py
     homeassistant/components/motion_blinds/__init__.py
     homeassistant/components/motion_blinds/const.py
diff --git a/homeassistant/components/modbus/modbus.py b/homeassistant/components/modbus/modbus.py
index 2e5892dbf1d..0826f4d5794 100644
--- a/homeassistant/components/modbus/modbus.py
+++ b/homeassistant/components/modbus/modbus.py
@@ -310,6 +310,8 @@ class ModbusHub:
         """Convert async to sync pymodbus call."""
         if self._config_delay:
             return None
+        if not self._client:
+            return None
         if not self._client.is_socket_open():
             return None
         async with self._lock: