diff --git a/library/core/src/main/java/com/google/android/exoplayer2/upstream/Loader.java b/library/core/src/main/java/com/google/android/exoplayer2/upstream/Loader.java
index 02ccfafa89..02e9a32116 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/upstream/Loader.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/upstream/Loader.java
@@ -420,7 +420,9 @@ public final class Loader implements LoaderErrorThrower {
 
     @Override
     public void run() {
-      sendEmptyMessage(0);
+      if (getLooper().getThread().isAlive()) {
+        sendEmptyMessage(0);
+      }
     }
 
     @Override