diff --git a/pgx/core.py b/pgx/core.py
index dbbd6c706..fb7bff71b 100644
--- a/pgx/core.py
+++ b/pgx/core.py
@@ -233,7 +233,7 @@ def observe(self, state: State, player_id: Optional[Array] = None) -> Array:
             player_id = state.current_player
         else:
             warnings.warn(
-                "[Pgx] player_id argument in `Env.observe` is deprecated. Will be removed in the future.",
+                "[Pgx] player_id argument in `Env.observe` is deprecated. This argument will be removed in the future.",
                 DeprecationWarning,
             )