diff --git a/psc-flink/src/main/java/com/pinterest/flink/connector/psc/sink/PscWriter.java b/psc-flink/src/main/java/com/pinterest/flink/connector/psc/sink/PscWriter.java
index 03a6e7d..eaf7394 100644
--- a/psc-flink/src/main/java/com/pinterest/flink/connector/psc/sink/PscWriter.java
+++ b/psc-flink/src/main/java/com/pinterest/flink/connector/psc/sink/PscWriter.java
@@ -430,6 +430,9 @@ private void registerMetricSync() {
                     if (closed) {
                         return;
                     }
+                    if (byteOutMetric == null || byteOutMetric.metricValue() == null) {
+                        return;
+                    }
                     long outgoingBytesUntilNow = ((Number) byteOutMetric.metricValue()).longValue();
                     long outgoingBytesSinceLastUpdate =
                             outgoingBytesUntilNow - latestOutgoingByteTotal;