Charlie Ngatai's timing is usually impeccable - running the perfect line to collect a pass and bust through the slightest of holes.

But the Chiefs midfielder has picked exactly the wrong time to find himself caught up in the fog of concussion, missing Friday's clash with the Waratahs and now left waiting to hear whether his name will be called in Sunday's All Blacks squad announcement.

Ngatai has not featured for the Chiefs since suffering a head knock in the loss to the Highlanders on May 7 and, while he was initially expected to be deemed fit for the trip to Sydney, coach Dave Rennie has adopted an understandably cautious approach with the second five's health.

After the way he had performed in the opening 10 weeks of the competition, Ngatai's Super Rugby form made him a certainty to earn inclusion for the June internationals against Wales. The only question appeared whether he or the experienced Ryan Crotty would take the No 12 jersey.


But Ngatai's lack of match practise may count against him when the team is named on Sunday morning. The first test at Eden Park will mark more than a month since Ngatai last ran out on a rugby field, meaning the 25-year-old must be an unlikely bet to earn his first start in black.

Given the amount of talent the All Blacks have lost among their midfield ranks, though, Ngatai should still see himself rewarded with a spot in the 32-man squad, especially since Rennie was confident his key man's concussion had almost cleared.

"He's improved but just not quickly enough," the coach said. "We're really cautious around all the concussions, but I'm pretty confident that if we had a game next week he'd be playing."

Ngatai's absence means the impressive pairing of Seta Tamanivalu and Anton Lienert-Brown will continue the encouraging partnership they formed in last weekend's win over the Rebels, with Rennie opting for only one injury-enforced change to his starting XV.

Canterbury loose forward Tom Sanders comes into the side in place of Michael Leitch, with the Japanese captain today having an operation to repair the thumb he dislocated while helping the Chiefs back to the top of the table.

With Leitch facing an eight-to-10 week recovery period, Rennie was hopeful the No 8 could recover in time to feature in the playoffs - should the Chiefs punch their ticket in the final three games after the international break - but will in the meantime rely on Sanders and Maama Vaipulu. And with the latter last weekend suffering a head knock of his own while playing club rugby, Sanders has received the first crack.

"Tom's been really good," Rennie said. "He's had a couple of injuries and a concussion that took him out for a few weeks. But until maybe the last couple of weeks, every time he's been available he's started. He's got a lot of footy under his belt and he's learning lots, so we'll need a big one out of him."

Chiefs team to play the Waratahs in Sydney on Friday night:

Damian McKenzie, Toni Pulu, Seta Tamanivalu, Anton Lienert-Brown, James Lowe, Aaron Cruden (c), Brad Weber, Tom Sanders, Sam Cane (c), Taleni Seu, Brodie Retallick, Dominic Bird, Hiroshi Yamashita, Nathan Harris, Mitchell Graham.

Reserves: Hika Elliot, Kane Hames, Siegfried Fisi'ihoi, Michael Allardice, Lachlan Boshier, Kayne Hammington, Andrew Horrell, Sam Vaka.