diff --git a/detect_secrets/core/upgrades/v0_12.py b/detect_secrets/core/upgrades/v0_12.py
index cc9e86239..793f0c8f4 100644
--- a/detect_secrets/core/upgrades/v0_12.py
+++ b/detect_secrets/core/upgrades/v0_12.py
@@ -5,8 +5,8 @@
 def upgrade(baseline: Dict[str, Any]) -> None:
     if 'exclude_regex' in baseline:
         baseline['exclude'] = {
-            'files': None,
-            'lines': baseline.pop('exclude_regex'),
+            'files': baseline.pop('exclude_regex'),
+            'lines': None,
         }
 
     baseline['word_list'] = {