diff --git a/wp-admin/ms-upgrade-site.php b/wp-admin/ms-upgrade-site.php
index f741be6d74..265b504eea 100644
--- a/wp-admin/ms-upgrade-site.php
+++ b/wp-admin/ms-upgrade-site.php
@@ -33,7 +33,8 @@ switch ( $action ) {
 			echo "<ul>";
 			foreach ( (array) $blogs as $details ) {
 				if ( $details['spam'] == 0 && $details['deleted'] == 0 && $details['archived'] == 0 ) {
-					$siteurl = $wpdb->get_var("SELECT option_value from {$wpdb->base_prefix}{$details['blog_id']}_options WHERE option_name = 'siteurl'");
+					$blog_prefix = $wpdb->get_blog_prefix( $details[ 'blog_id' ] );
+					$siteurl = $wpdb->get_var( "SELECT option_value from {$blog_prefix}options WHERE option_name = 'siteurl'" );
 					echo "<li>$siteurl</li>";
 					$response = wp_remote_get( trailingslashit( $siteurl ) . "wp-admin/upgrade.php?step=1", array( 'timeout' => 120, 'httpversion' => '1.1' ) );
 					if ( is_wp_error( $response ) )