diff --git a/spacy/syntax/_parser_model.pyx b/spacy/syntax/_parser_model.pyx
index 5615fcea1..fd87aab2b 100644
--- a/spacy/syntax/_parser_model.pyx
+++ b/spacy/syntax/_parser_model.pyx
@@ -201,6 +201,8 @@ class ParserModel(Model):
         return step_model, finish_parser_update
 
     def resize_output(self, new_output):
+        if new_output == self.upper.nO:
+            return
         smaller = self.upper
         larger = Affine(new_output, smaller.nI)
         larger.W *= 0