diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index b748193e44f..c10bb62aab4 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -562,6 +562,14 @@ class PurchaseOrderLine(models.Model):
             self.product_uom = self.product_id.uom_po_id
         result['domain'] = {'product_uom': [('category_id', '=', self.product_id.uom_id.category_id.id)]}
 
+        product_lang = self.product_id.with_context({
+            'lang': self.partner_id.lang,
+            'partner_id': self.partner_id.id,
+        })
+        self.name = product_lang.display_name
+        if product_lang.description_purchase:
+            self.name += '\n' + product_lang.description_purchase
+
         seller = self.product_id._select_seller(
             self.product_id,
             partner_id=self.partner_id,
@@ -569,6 +577,12 @@ class PurchaseOrderLine(models.Model):
             date=self.order_id.date_order and self.order_id.date_order[:10],
             uom_id=self.product_uom)
 
+        if seller or not self.date_planned:
+            self.date_planned = self._get_date_planned(seller).strftime(DEFAULT_SERVER_DATETIME_FORMAT)
+
+        if not seller:
+            return result
+
         fpos = self.order_id.fiscal_position_id
         self.taxes_id = fpos.map_tax(self.product_id.supplier_taxes_id)
 
@@ -576,16 +590,7 @@ class PurchaseOrderLine(models.Model):
         if price_unit and seller and self.order_id.currency_id and seller.currency_id != self.order_id.currency_id:
             price_unit = seller.currency_id.compute(price_unit, self.order_id.currency_id)
         self.price_unit = price_unit
-        if seller or not self.date_planned:
-            self.date_planned = self._get_date_planned(seller).strftime(DEFAULT_SERVER_DATETIME_FORMAT)
 
-        product_lang = self.product_id.with_context({
-            'lang': self.partner_id.lang,
-            'partner_id': self.partner_id.id,
-        })
-        self.name = product_lang.display_name
-        if product_lang.description_purchase:
-            self.name += '\n' + product_lang.description_purchase
 
 
 class ProcurementRule(models.Model):