diff --git a/addons/mrp/schedulers.py b/addons/mrp/schedulers.py
index 509d50b46b9..fb9b1edf6a8 100644
--- a/addons/mrp/schedulers.py
+++ b/addons/mrp/schedulers.py
@@ -197,7 +197,7 @@ class mrp_procurement(osv.osv):
                     if reste > 0:
                         qty += op.qty_multiple - reste
                     newdate = DateTime.now() + DateTime.RelativeDateTime(
-                            days=op.product_id.seller_delay)
+                            days=int(op.product_id.seller_delay))
                     if op.product_id.supply_method == 'buy':
                         location_id = op.warehouse_id.lot_input_id
                     elif op.product_id.supply_method == 'produce':
diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index f512406738b..887950bc746 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -522,7 +522,7 @@ class purchase_order_line(osv.osv):
                         'uom': uom,
                         'date': date_order,
                         })[pricelist]
-        dt = (datetime.now() + relativedelta(days=seller_delay or 0.0)).strftime('%Y-%m-%d %H:%M:%S')
+        dt = (datetime.now() + relativedelta(days=int(seller_delay) or 0.0)).strftime('%Y-%m-%d %H:%M:%S')
         prod_name = self.pool.get('product.product').name_get(cr, uid, [prod.id])[0][1]