The ex-Red Devils striker has asked for fans to be patient with the new full-back, labeling the summer signing as "somebody to look out for" in the future
Buttner, a summer signing from Vitesse Arnhem, has found Patrice Evra stiff competition for the left-back spot, though he did enjoy a start in Saturday’s FA Cup clash with West Ham.
But ex-Red Devils goalscorer van Nistelrooy believes United fans should not be deterred by this, and claims the 23-year-old could well be a future star at the club.
"Alexander has made a great start," he told Manchester United’s official website. "He needs a bit more time as he's definitely somebody for the future.
"He's been getting games in the Champions League. For him, it's a dream come true. He's got the ability and needs to learn to obtain more experience and he's definitely somebody to look out for."