diff --git a/devito/operator/operator.py b/devito/operator/operator.py
index a8408e023f..1c9989c4e6 100644
--- a/devito/operator/operator.py
+++ b/devito/operator/operator.py
@@ -648,15 +648,15 @@ def _prepare_arguments(self, autotune=None, **kwargs):
         for d in reversed(toposort):
             args.update(d._arg_values(self._dspace[d], grid, **kwargs))
 
-        # Process Objects
-        for o in self.objects:
-            args.update(o._arg_values(grid=grid, **kwargs))
-
         # Process SubDimensionThicknesses
         for p in self.parameters:
             if isinstance(p, SubDimensionThickness):
                 args.update(p._arg_values(grid=grid, **kwargs))
 
+        # Process Objects
+        for o in self.objects:
+            args.update(o._arg_values(grid=grid, **kwargs))
+
         # Purge `kwargs`
         kwargs.pop('args')
         kwargs.pop('metadata')
diff --git a/devito/types/dimension.py b/devito/types/dimension.py
index 2b22d8c9fe..4d622ac7c3 100644
--- a/devito/types/dimension.py
+++ b/devito/types/dimension.py
@@ -23,7 +23,6 @@
 
 
 Thickness = namedtuple('Thickness', 'left right')
-SubDimensionOffset = namedtuple('SubDimensionOffset', 'value extreme thickness')
 
 
 class Dimension(ArgProvider):