diff --git a/dask_ml/model_selection/utils.py b/dask_ml/model_selection/utils.py
index <HASH>..<HASH> 100644
--- a/dask_ml/model_selection/utils.py
+++ b/dask_ml/model_selection/utils.py
@@ -4,6 +4,7 @@ from distutils.version import LooseVersion
 
 import dask
 import dask.array as da
+import dask.dataframe as dd
 import scipy.sparse as sp
 from dask.base import tokenize
 from dask.delayed import Delayed, delayed
@@ -45,7 +46,7 @@ def to_indexable(*args, **kwargs):
     else:
         indexable = _indexable
     for x in args:
-        if x is None or isinstance(x, da.Array):
+        if x is None or isinstance(x, (da.Array, dd.DataFrame)):
             yield x
         elif is_dask_collection(x):
             yield delayed(indexable, pure=True)(x)
update indexable() to just yield dask dataframes (issue #<I>) (#<I>)

* update indexable() to just yield dask dataframes, as mentioned in issue #<I>