diff --git a/src/mips/stub-cache-mips.cc b/src/mips/stub-cache-mips.cc
index 3681120a7d..e7c8aef6a6 100644
--- a/src/mips/stub-cache-mips.cc
+++ b/src/mips/stub-cache-mips.cc
@@ -537,7 +537,8 @@ void StubCompiler::GenerateStoreTransition(MacroAssembler* masm,
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   // Perform map transition for the receiver if necessary.
-  if (object->map()->unused_property_fields() == 0) {
+  if (details.type() == FIELD &&
+      object->map()->unused_property_fields() == 0) {
     // The properties must be extended before we can store the value.
     // We jump to a runtime call that extends the properties array.
     __ push(receiver_reg);