The youngster arrived on an initial loan from Chelsea a year ago, which was made permanent in the summer.
However, he has not put in the most impressive of displays at left-back for the Magpies.
Former Republic of Ireland international Anderson told BBC Radio Newcastle: "I have doubts about him from a defensive point of view. Some of the positions he takes up aren't great.
"I think it is mainly the case that he isn't defensive minded. He wants to get on the ball, he wants to get forward, he wants to join in, which I know is your modern day full-back and I appreciate that, but when it comes to defending you have got to do it.
"You have to be in the right areas, you can't leave holes in behind you and, in the games he has played this season, they have been there for everyone to see.
"He is still 20 years of age but whether he sees his future long-term as a full-back or not, I don't know. The boy can play the game, there is no doubt about it, I just feel defensively, he doesn't think defensively. All his thoughts are about getting forward and joining in and when it is coming the other way, he doesn't think 'danger'."