diff --git a/src/skmatter/sample_selection/_base.py b/src/skmatter/sample_selection/_base.py
index 6026bce7b..22c3ac496 100644
--- a/src/skmatter/sample_selection/_base.py
+++ b/src/skmatter/sample_selection/_base.py
@@ -58,7 +58,7 @@ class FPS(_FPS):
     Parameters
     ----------
 
-    initialize: int, list of int, or 'random', default=0
+    initialize: int, list of int, ndarray of int, or 'random', default=0
         Index of the first selection(s). If 'random', picks a random
         value when fit starts. Stored in :py:attr:`self.initialize`.