diff --git a/lib/defaults.js b/lib/defaults.js
index eaee1898a0..d00f248160 100644
--- a/lib/defaults.js
+++ b/lib/defaults.js
@@ -8,8 +8,9 @@ var DEFAULT_CONTENT_TYPE = {
   'Content-Type': 'application/x-www-form-urlencoded'
 };
 
-function setContentTypeIfUnset(headers, value) {
-  if (!utils.isUndefined(headers) && utils.isUndefined(headers['Content-Type'])) {
+function setContentTypeIfUnset(
+, value) {
+  if (utils.isUndefined(headers['Content-Type'])) {
     headers['Content-Type'] = value;
   }
 }
@@ -71,7 +72,7 @@ var defaults = {
       setContentTypeIfUnset(headers, 'application/x-www-form-urlencoded;charset=utf-8');
       return data.toString();
     }
-    if (utils.isObject(data) || (headers && headers['Content-Type'] === 'application/json')) {
+    if (utils.isObject(data) || (headers['Content-Type'] === 'application/json')) {
       setContentTypeIfUnset(headers, 'application/json');
       return stringifySafely(data);
     }