diff --git a/pyomo/core/base/initializer.py b/pyomo/core/base/initializer.py
index 5863966e6f9..991feb0450d 100644
--- a/pyomo/core/base/initializer.py
+++ b/pyomo/core/base/initializer.py
@@ -157,7 +157,10 @@ def Initializer(
             # 'int').  We will just have to assume this is a "normal"
             # IndexedCallInitializer
             return IndexedCallInitializer(arg)
-        if len(_args.args) - len(arg.args) == 1 and _args.varargs is None:
+        _positional_args = set(_args.args)
+        for key in arg.keywords:
+            _positional_args.discard(key)
+        if len(_positional_args) - len(arg.args) == 1 and _args.varargs is None:
             return ScalarCallInitializer(arg)
         else:
             return IndexedCallInitializer(arg)
diff --git a/pyomo/core/tests/unit/test_initializer.py b/pyomo/core/tests/unit/test_initializer.py
index 655ca375af5..5767406bdf7 100644
--- a/pyomo/core/tests/unit/test_initializer.py
+++ b/pyomo/core/tests/unit/test_initializer.py
@@ -595,6 +595,17 @@ def fcn(k, i, j, m):
         self.assertFalse(a.contains_indices())
         self.assertEqual(a(None, None), 572)
 
+        def fcn(m, k, i, j):
+            return i * 100 + j * 10 + k
+
+        part = functools.partial(fcn, i=2, j=5, k=7)
+        a = Initializer(part)
+        self.assertIs(type(a), ScalarCallInitializer)
+        self.assertTrue(a.constant())
+        self.assertFalse(a.verified)
+        self.assertFalse(a.contains_indices())
+        self.assertEqual(a(None, None), 257)
+
     @unittest.skipUnless(pandas_available, "Pandas is not installed")
     def test_dataframe(self):
         d = {'col1': [1, 2, 4]}