Sam Vesty has backed Taqele Naiyaravoro to come good for Saints - even though the powerhouse wing has been forced to 'jump in at the deep end'.
Naiyaravoro was given last weekend off as Saints took the chance to hand him a breather after a hectic start to life in England.
The Australian ace played a full Super Rugby season before arriving in England, propelling the NSW Waratahs to the semi-finals of the competition.
He scored 15 tries along the way before moving to Northampton two days before his first appearance in the club's colours, in a Wanderers game against Leicester on September 3.
Naiyaravoro made his first-team debut against Saracens on September 15 and had started each of the three games that followed before being rested for the Challenge Cup clash with Clermont Auvergne last Saturday.
And when asked about the decision to leave the 26-year-old out of the squad, attack coach Vesty said: "He's played a lot of rugby recently.
"He came in, jumped in and didn't have a massive amount of training base.
"He probably needed an opportunity to just train so we could look after him.
"It (his fitness) is something he will always have to work on because he's a very big man and the game goes fast these days.
"But he's put in the effort and I've seen him doing a lot of running over these past couple of weeks."
Naiyaravoro's most influential showing to date came at Bristol on September 29.
He scored a try and caused plenty of problems for the home side as Saints won 45-40 at Ashton Gate.
And Vesty said: "He's devastating on the ball and we want to see as much of that as we can.
"Of course players always want a pre-season and he's jumped in at the deep end.
"But he's a good player and he understands what he's trying to do.
"I have all the faith that although he's jumping straight in, he can do it well."