diff --git a/src/Client.php b/src/Client.php
index 2932d1bb..345a57a8 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -142,7 +142,7 @@ class Client implements ClientInterface
             return $uri instanceof UriInterface ? $uri : new Psr7\Uri($uri);
         }
 
-        return Psr7\Uri::resolve(Psr7\uri_for($config['base_uri']), $uri);
+        return Psr7\Uri::resolve($config['base_uri'], $uri);
     }
 
     /**
@@ -255,7 +255,7 @@ class Client implements ClientInterface
             unset($options['save_to']);
         }
 
-        // exceptions -> http_error
+        // exceptions -> http_errors
         if (isset($options['exceptions'])) {
             $options['http_errors'] = $options['exceptions'];
             unset($options['exceptions']);
@@ -297,9 +297,14 @@ class Client implements ClientInterface
         }
 
         if (isset($options['multipart'])) {
-            $elements = $options['multipart'];
+            $options['body'] = new Psr7\MultipartStream($options['multipart']);
             unset($options['multipart']);
-            $options['body'] = new Psr7\MultipartStream($elements);
+        }
+
+        if (isset($options['json'])) {
+            $options['body'] = \GuzzleHttp\json_encode($options['json']);
+            unset($options['json']);
+            $options['_conditional']['Content-Type'] = 'application/json';
         }
 
         if (!empty($options['decode_content'])
@@ -353,13 +358,6 @@ class Client implements ClientInterface
             unset($options['query']);
         }
 
-        if (isset($options['json'])) {
-            $jsonStr = \GuzzleHttp\json_encode($options['json']);
-            $modify['body'] = Psr7\stream_for($jsonStr);
-            $options['_conditional']['Content-Type'] = 'application/json';
-            unset($options['json']);
-        }
-
         // Ensure that sink is not an invalid value.
         if (isset($options['sink'])) {
             // TODO: Add more sink validation?