diff --git a/laravel/database/schema/grammars/sqlserver.php b/laravel/database/schema/grammars/sqlserver.php
index 6cc912f7..5f756c2e 100644
--- a/laravel/database/schema/grammars/sqlserver.php
+++ b/laravel/database/schema/grammars/sqlserver.php
@@ -138,7 +138,7 @@ public function primary(Table $table, Fluent $command)
 	{
 		$name = $command->name;
 
-		$columns = $this->columnize($command->$columns);
+		$columns = $this->columnize($command->columns);
 
 		return 'ALTER TABLE '.$this->wrap($table)." ADD CONSTRAINT {$name} PRIMARY KEY ({$columns})";
 	}