Vieira is yet to make a serious break through into the Wigan Athletic first team, he is an outstanding prospect however and this will give Paul Jewell a great chance to see what the forward can do in competitive action.
Cobblers boss Colin Calderwood told the club's official website: "We have seen Vieira in action for their reserves and we are grateful to Paul Jewell for letting him come to us, because there were other clubs interested.
"I'm sure he can do very well for us. He thinks he can be an advantage to us and he is a very good prospect"