Matt Proctor and Owen Franks are expected to arrive at Franklin's Gardens on Thursday.
The All Blacks aces, who had been on standby for World Cup duty until last weekend, boarded the same plane in New Zealand as they got set to wing their way to Northampton.
But Proctor won't be available for selection immediately as the centre is currently recovering from a pectoral injury.
"They both ended up on the same plane and they're in the air now," said Saints boss Chris Boyd at Wednesday afternoon's media session.
"They'll be here tomorrow, both of them.
"Matt Proctor is still rehabbing after a pectoral operation he had so he's still two or three weeks away (from playing).
"Owen Franks, if he had his way he'd be on the bench here on Friday night. He just wants to rip into it as soon as he can.
"Owen will come in for selection over the next couple of weeks and Matt will probably be a couple of weeks after that."
When asked how much he looking forward to being able to select the duo, Boyd said: "Paul Hill has been good for us, Ehren Painter has been good for us and Karl Garside, the young fella we picked up out of Ampthill, has been really good for us so it will give us a little more depth, experience and solidity.
"It will be good to see them here and running out at Franklin's Gardens."