diff --git a/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/SeekableByteChannelPrefetcher.java b/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/SeekableByteChannelPrefetcher.java
index dbdd4e5a..41632f8c 100644
--- a/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/SeekableByteChannelPrefetcher.java
+++ b/google-cloud-nio/src/main/java/com/google/cloud/storage/contrib/nio/SeekableByteChannelPrefetcher.java
@@ -357,8 +357,10 @@ public ByteBuffer fetch(long position) throws InterruptedException, ExecutionExc
       nbMiss++;
       ensureFetching(blockIndex);
       candidate = fetching;
-      buf = candidate.getBuf();
-      full.add(candidate);
+      if (candidate != null) {
+        buf = candidate.getBuf();
+        full.add(candidate);
+      }
       fetching = null;
       ensureFetching(blockIndex + 1);
       return buf;