diff --git a/core/src/main/java/hudson/triggers/Trigger.java b/core/src/main/java/hudson/triggers/Trigger.java
index ecdb357080999633c5f3e207f797ee79103f2dc4..8fe23bee2d8f0af7cd4f7e49807d4ff334456972 100644
--- a/core/src/main/java/hudson/triggers/Trigger.java
+++ b/core/src/main/java/hudson/triggers/Trigger.java
@@ -110,7 +110,7 @@ public abstract class Trigger<J extends Item> implements Describable<Trigger<?>>
         return spec;
     }
 
-    private Object readResolve() throws ObjectStreamException {
+    protected Object readResolve() throws ObjectStreamException {
         try {
             tabs = CronTabList.create(spec);
         } catch (ANTLRException e) {