diff --git a/rowers/dataprep.py b/rowers/dataprep.py
index 72d7cb91..9326cf35 100644
--- a/rowers/dataprep.py
+++ b/rowers/dataprep.py
@@ -182,9 +182,15 @@ def clean_df_stats(datadf, workstrokesonly=True, ignorehr=True,
     except KeyError:
         pass
 
-    datadf = datadf.clip(lower=0)
+
+    try:
+        datadf = datadf.clip(lower=0)
+    except TypeError:
+        pass
+
     datadf.replace(to_replace=0, value=np.nan, inplace=True)
 
+
     # return from positive domain to negative
     try:
         datadf['catch'] = -datadf['catch']