Harlequins are set to replace Bristol-bound Adrian Jarvis with the back-up to the best fly-half in the world.
Dean Richards' men look to have won the race to sign Auckland Blues fly half Nick Evans, who plays second fiddle to Dan Carter for the All Blacks, for next season.
A two-and-a-half year deal is being lined up for the versatile Evans, who can play at 10 or 15 and has 16 New Zealand caps, after Leicester dropped out of the race having signed Juan Hernandez from Stade Francais instead.
The signing will not be announced until the All Black squad for the summer tests against England are made known on the 1st June.
Meanwhile, Quins will select from an almost fully fit squad as they chase both a Premiership play-off and Heineken Cup place at home to Sale in their penultimate game of the season on Sunday.
Back row forward Tom Guest, 23, who has been quietly making a name for himself during Quins' late charge up the table, said: "If we want to get into the playoffs, these are the type of games to play in and win.
"Our final two games are huge and will be pressure situations. Sale at home in front of a packed house will be a tight affair, and if we can pull off a win we can look forward to going to Leicester and perhaps do the same there.
"The energy within the club is fantastic, despite our loss at London Irish, and we are raring to finish the season off in style."
Guest recently signed a two-year deal to stay at Quins and has been tipped for a place in the England Saxons squad for this summer's Churchill Cup.
He said: "I started the season just wanting to break into the first team squad on a regular basis. I've done that over the last few months now, and I can think about pushing on.
"The contract issue was resolved quite early on in the year, and it was nice to get it out of the way and concentrate on the rugby.
"It takes a bit of pressure off. I knew where I was going to be, and that has helped me put in the performances that I have done recently.
"The squad we are building is going to be a real force in the future, with players like Jordan Turner-Hall, Tosh Masson, Danny Care and Mike Brown to name but a few - and I want to be part of that too."