It is no surprise; the Fijian has been a revelation in Super League this term after initially joining the Black and Whites on trial from the British Army where he had been playing rugby union.
Naulago impressed enough to sign a permanent contract earlier this season and - with 10 tries in 13 games - Hull have now exercised a one-year extension clause in his contract.
The East Yorkshire club have been so impressed that they are already in talks with the soldier, who still serves as a Private in the Army, about extending it further.
Hull head coach Lee Radford said: "I'm over the moon that Ratu will be staying with us until at least another year because he's been showing nothing but huge strides in the right direction.
"If you compare where he was at back in pre-season to the way he is performing now, there is a phenomenal difference.
“One of the most exciting things is that he can still keep improving.
“There aren't many players in this modern day in age who are so easy to coach.
“But Ratu is a great listener and he's fantastic at adapting to different scenarios, so he's got a very exciting future ahead of him at this club.”