England and New Zealand have both suffered crucial losses before their meeting in Saturday’s first Test at Eden Park. The centre Billy Twelvetrees missed England’s final training session before Stuart Lancaster names his XV on Thursday morning – all but confirming his absence – while New Zealand lost the current IRB world player of the year, Kieran Read, to concussion, a condition he has battled all season.

Twelvetrees – who made a try-scoring debut against Scotland in the opening round of the 2013 Six Nations – had been a doubt since picking up an ankle injury on the first weekend of May and his absence means that Kyle Eastmond is likely to win his third cap. The diminutive former Rugby League man shone on last summer’s tour to Argentina but has endured a tricky 2013-14, falling out of favour at Bath amid rumours he might quit the club.

If, as expected, Eastmond and Freddie Burns – in the absence of Owen Farrell, Stephen Myler and George Ford – are to line up at fly-half and inside centre, then England will be fielding their fourth-choice players in those key positions.

While Read is a player of rare class, the immense depth of the All Blacks means that his absence does not pose quite the same headaches for Steve Hansen, who is able to call upon the services of Jerome Kaino once again after a stint in Japan. Having missed a number of Super Rugby games with concussion earlier in the season, Read woke on Monday with minor concussion-like symptoms after Crusaders’ 30-7 win over Western Force on Saturday.

While Kaino returned from Japan only six weeks ago, he has immediately hit his Super Rugby straps and was instrumental in Blues’ win over Hurricanes on Saturday – a game that England’s players enjoyed from the stands at Eden Park. Kaino led an immense defensive effort and carried with purpose, crossing for a try shortly after half-time.

As a World Cup winner, the threat he poses will be no secret to Lancaster and his men but his presence will change the point of attack. While Read, with his slick hands, supple movement and sharp feet, often operates out wide, Kaino’s is a less subtle threat, coming through the middle of the field with aggressive carries and tenacious tackling. “It’s hard to tell how big a loss Kieran will be, but what I’m sure of is that the standard of player who fills his shoes – whether that’s Kaino or somebody else – will be world class in their own right,” said England’s Joe Launchbury.

Whether Read was fit or not, it was possible that Kaino’s Super Rugby form would have forced him into the side at the expense of the Chiefs’ blindside Liam Messam but now both are likely to partner the captain, Richie McCaw, in the back row.

The All Blacks’ loose-forward stocks were further depleted by the withdrawal of McCaw’s understudy for the No7 jersey, Sam Cane, who suffered a knee fracture over the weekend. Steven Luatua, a surprise absentee from the initial squad, and Matt Todd of the Crusaders have been called up to deputise. In the backs the winger Julian Savea is a doubt for the first Test with a knee injury.Speaking after his side’s final training session before the naming of the side on Thursday, Hansen said: “We’re not prepared to risk him playing and that’s our decision, not his, and we’ll progress that day by day. Keiran’s frustrated, as you would be, but we’re very lucky we’ve got capable people who can fill his place, as Jerome Kaino and Victor Vito have been performing very well and Liam Messam is an incumbent.”

The confirmation of Read’s absence re-opened the concussion debate after New Zealand-born former England centre Shontayne Hape retired from the game this week amid concerns for his future health. Read’s All Black colleague Brodie Retallick, who has himself suffered with the condition, said it was not an issue to take lightly. He said: “You’re not sure when the symptoms are going to go away or when they’re going to return.

“You’ve just got to be patient and wait it out and wait for it to clear, because it’s something you don’t really want to mess around with.”

As articulate as he was on that issue, when questioned on the make-up of England’s side, Retallick failed to summon a single correct response, instead offering “Michael Laws” as an answer, presumably referring to Courtney Lawes, the Northampton lock currently in transit having competed in the Premiership final. Michael Laws is in fact a New Zealand politician and broadcaster.