diff --git a/play_by_play_parser/players_on_court.py b/play_by_play_parser/players_on_court.py
index e8f987b..bbbb2b1 100644
--- a/play_by_play_parser/players_on_court.py
+++ b/play_by_play_parser/players_on_court.py
@@ -89,7 +89,7 @@ def extract_data(url):
 players_subbed_in_at_each_period = first_event_of_period[first_event_of_period['SUB'] == 'IN'][
     ['PLAYER_ID', 'PERIOD', 'SUB']]
 
-periods = players_subbed_in_at_each_period['PERIOD'].drop_duplicates().values.tolist()
+periods = play_by_play['PERIOD'].drop_duplicates().values.tolist()
 
 rows = []
 for period in periods: