diff --git a/fmriprep/workflows/bold/stc.py b/fmriprep/workflows/bold/stc.py
index 2e348de67..6f40ce308 100644
--- a/fmriprep/workflows/bold/stc.py
+++ b/fmriprep/workflows/bold/stc.py
@@ -27,6 +27,7 @@
 .. autofunction:: init_bold_stc_wf
 
 """
+import numpy as np
 import nibabel as nb
 from nipype.pipeline import engine as pe
 from nipype.interfaces import utility as niu, afni